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THE 
PRODUCTION  AND  HANDLING 


OF 


CLEAN  MILK> 

INCLUDING 

PRACTICAL   MILK   INSPECTION 


BY 

KENELM   WINSLOW,  M.D.;  M.D.V.;  B.A.S.  (Harv.) 

Formerly  Instructor  in  Bussey  Agricultural  Institute  and  Assistant 

Professor  in  the  Veterinary  School  of  Harvard  University. 

Author  of  a  text  book  on  Veterinary  Materia  Medica 

and  Therapeutics,  Chairman  of  the  Committee 

on  Milk  of  the    Washington    State 

Medical  Association.,  etc. 


AND 


Essentials  of  Milk  Bacteriology 


BY 


H.  W.  HILX,  M.D. 


Minnesota  State  Board  of  Health  Laboratories,  Chairman  of  the  Committee  on 

Laboratories  of  the  American  Public  Health  Association,  formerly  Director 

Boston  Board  of  Health  Bacteriological  Laboratory 


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NEW  YORK 

WILXIAM    R.    JENKINS    CO. 

publishers 

851  &  853  Sixth  Avenue 


Copyright,  I907,  1909 

By  William  R.  Jenkins  Co. 

All  rights  reserved. 


[Registered  at  Stationers'  Hall,  London] 
Printed  in  the  United  States  of  America 


PRINTED  BY  THE 

Press  of  William  R.  Jenkins  Co. 
New  York 


PREFACE  TO  SECOND  EDITION 


The  writer  and  publishers  feel  gratified  that  a  second 
edition  of  this  work  is  called  for  within  a  little  over  a  year 
from  its  first  appearance. 

Such  rapid  advances  have  occurred  in  the  knowledge 
of  subjects  herein  treated  that  it  has  been  found  necessary 
to  very  materially  add  to  and  alter  the  former  text — so 
much  so,  that  many  chapters  of  the  present  volume  have 
been  re-written  and  very  considerably  expanded. 

The  attempt  has  been  made  in  this  revision  to  so 
extend  the  scope  of  the  original  work  as  to  supply  to 
veterinary,  agricultural  and  dairy  students,  and  to  health 
officers,  a  text-book  on  practical  milk  inspection  and  dairy 
hygiene,  which  are  becoming  of  such  importance  to  the 
public  health. 

Moreover,  the  author  has  had  the  advantage  of  the 
collaboration  of  Dr.  H.  W.  Hill,  whose  work  in  milk 
bacteriology  is  well  known. 

The  writer  also  desires  to  acknowledge  his  grateful 
indebtedness  to  Professor  Conn  for  his  generosity  in  per- 
mitting the  use  of  the  laboratory  experiments  in  dairy 
bacteriology. 

Both  of  these  additions  should  prove  of  great  benefit 
.to  students  of  milk  bacteriology. 

Kenelm   Winslow. 


PREFACE  TO  FIRST  EDITION 


The  writer  is  a  graduate  in  agricultural  science,  in  veter- 
inary and  human  medicine,  and  has  been  connected  with  a 
laboratory  in  which  is  examined  the  milk  supply  of  a  large 
city,  and  finally  has  had  considerable  practical  experience  in 
the  production  and  distribution  of  clean  milk. 

These  facts  are  simply  mentioned  to  show  that  the 
book  is  written  from  various  points  of  view. 

Much  blame  is  attached  to  sundry  persons  engaged  in 
vending  milk,  but  the  unfortunate  farmer  is  apt  to  receive 
an  unjust  share  because  of  the  commonly  unclean  and  there- 
fore unsanitary  condition  of  most  market  milk.  While  city 
contractors  and  dealers  may  have  much  influence  in 
instructing  and  requiring  the  farmer  to  live  up  to  recognized 
standards  of  cleanliness,  yet,  after  all,  the  chief  responsibility 
lies  with  the  consumer.  The  essential  object  in  the  clean 
milk  crusade  should  be  to  awaken  the  public  to  the  dangers 
of  unclean  milk  and  to  emphasize  the  fact  that  it  is  impos- 
sible to  produce  and  obtain  clean  milk  except  at  unusual 
expense. 

When  the  public  is  sufficiently  aroused  to  the  evils  of 
consuming  unclean  milk  and  evinces  willingness  to  pay  for 
clean  milk,  there  will  be  no  difficulty  about  its  production. 
It  is  merely  a  question  of  supply  and  demand. 


PREFACE 

It  is  not  generally  known  that  the  farmer  sometimes 
receives  but  one-quarter  of  the  retail  price  of  milk  (frequently 
but  2  cents  a  quart),  and  he  can  hardly  be  expected  to 
undertake  a  considerably  increased  expenditure  for  the 
production  of  clean  milk — this  being  the  case. 

There  is  probably  more  interest  being  shown  in  this 
and  other  countries  in  a  pure  milk  supply  than  ever  before. 
For  this  reason  it  should  be  a  comparatively  easy  task  for 
any  individual  desiring  to  produce  clean  milk  in  any  con- 
siderable community  to  find  a  sufficient  patronage,  particu- 
larly if  the  local  medical  profession  is  asked  to  assist, 
always  providing  that  the  proper  standard  is  constantly  and 
conscientiously  maintained.  The  idea  of  financial  return 
must  be  subordinated  to  this,  and  yet  a  reasonable  profit 
can  and  must  be  had  to  sustain  the  required  standard. 

The  aim  of  this  book  is  to  provide  a  working  guide  for 
those  pursuing  or  wishing  to  pursue  one  of  the  most  whole- 
some, worthy  and  laudable  undertakings — the  production 
of  clean  milk. 

Most  of  the  books  at  our  command  either  touch  the 
subject  in  a  general  manner  or  else  describe  special  phases 
of  it  in  detail.  The  attempt  has  here  been  made  to  cover 
the  whole  ground  in  as  small  compass  as  possible.  That 
such  an  attempt  must  fall  short  the  author  is  aware,  as  the 
topic  of  feeding  cows  alone  (accorded  but  a  chapter  in  this 
book)  can  only  be  fully  treated  in  a  large  volume  devoted 
wholly  to  this  subject. 

Objection  may  be  made  to  the  recommendation  of 
particular   apparatus    of    certain   manufacturers.       But  the 


PREFACE 

writer  has  been  so  desirous  of  making  the  book  practical 
that  it  has  been  deemed  essential  to  choose  special  appliances 
in  order  to  avoid  generalities  and  vagueness. 

While  endeavoring  to  select  the  best,  it  does  not  follow 
that  other  appliances  are  not  as  good,  or  even  better  than 
those  advised ;  but  the  author  can  truthfully  affirm  that 
both  he  and  his  publisher  are  entirely  free  from  the  remotest 
financial  interest  in  advertising  any  special  dairy  appliances. 
Such  appliances  are  undergoing  the  most  wonderful  and 
rapid  improvement,  almost  from  day  to  day. 

Kenelm   Winslow. 


CONTENTS 


CHAP.  PAGB 

I.     Germs  in  their  General  Relations  to  Milk          .  i 
II.     Composition  op  Milk  and  Cream  and  their  Pro- 
ducts       42 

III.  Milk  Products 54 

IV.  Feeding  for  Milk 66 

V.     Housing  and  Care  of  Cows 80 

VI.  Handling  of  Milk  and  Cream 101 

VII.  Cost  of  Producing  and  Distributing  Clean  Milk  .     146 

VIII,  Some  Hints  Concerning  Milk  Distribution     .         .162 

IX.  Milk  Inspection 174 

X.  Essentials  of  Milk  Bacteriology    ....     233 

XI.  Quantitative  Bacterial  Analysis  of  Milk     .         .241 

XII.  Media  Making  and  Apparatus  Required  for  Bac- 
terial Analysis  of  Milk     .....     262 

XIII.  Classification  and  Identification  of  Bacteria — 

Glossary — Adjustment  of  Reaction  of  Media    281 

XIV.  Laboratory  Work  in  Dairy  Bacteriology      .        .     293 
APPENDIX.     Dairy  Cows,  their  Records  and  Value — 

Plans  of  Barns  and  Milk  Houses— Milking  Machines 
Keeping  Accounts — Disinfection — Tuberculin  Test- 
ing, etc .        .        „        .313 

INDEX      .         .         .         .         .         .         .         .         .         .         .     359 


LIST  OF  ILLUSTRATIONS 


Frontispiece — Babcock  Flask,  showing  fat  in  neck. 

Fig.  Page 

i     General  Shape  of  Bacteria 4 

2  The  Constituent  Elements  of  Milk        .         .          .        follows       44 
Sketch  A — Two  Methods  of  Ventilating  a  Dairy  Barn         .       85 
Sketch  B— Method  of  Ventilating  a  Lean-to  Stable       .          .       86 
Sketch  C — Section  of  the  Cow  Stable  at  the  Wisconsin  Ex- 
periment Station 87 

Sketch  D — Showing  Rutherford  System  of  Ventilation         .       90 

3  Cow  Tail-holder 99 

4  Good  Type  of  Milking  Suit  and  Pail 102 

5  Iron  Milking  Stool       .          .         .         .         .         .          .  103 

6  Milking  Stool 103 

7  The  Gurler  Milk  Pail 104 

8  A  Recent  Improvement  of  the  Gurler  Pail   ....      104 

9  Modification  of  Stewart's  Milk  Pail 105 

10  Stadmueller  Covered  Pail     .         .         .         .         .         .         .106 

11  The  North  Covered  Pail 106 

12  The  Trueman  Covered  Pail  .         .         .         .         .         .107 

13  Revolving  Dairy  Filter 108 

14  Metal  Frame  on  which  Milk  Pails  are  Set    .          .         .          .109 

15  The  Conical  Cooler 113 

16  The  Star  Cooler 114 

17  Tubular  Cooler    .         .         .         .         .         .         .         „         .114 

18  Star  Milk  Cooler 115 

19  Star  Milk  Cooler 115 

20  Star  Milk  Cooler 116 

21  Trap  Milk  Strainer       .          .         .         .         .         .         .  117 

22  Covered  Milk  Cooler    .          .         .         .         .         .         .         .119 

23  Parts  of  Cooler 1 20 


LIST  OF  ILL  US TR A  TIONS 
Fig. 

24  An  Arrangement  of  Cooler  and  Hand  Bottle- Filler 

25  Wash  Sink 

26  Various  Forms  of  Brushes    . 

27  Milk  Can  Jacket 

28  Star  Side-Bar  Filler      . 

29  Star  High  Pressure  Sterilizer 

30  Star  Sterilizer 

31  Bottle  Brush 

32  Star  Metal  Wash  Sink 

33  Star  Bottle  Washing  Outfit 

34  Steam  Heating  Tee 

35  Glass  Dairy  Thermometer    . 

36  Machine  for  Chopping  Ice  used  to  pack  about  milk  bottles 

37  Banjo  Conductor  for  carrying  milk  through  a  wall 

38  Cylinder  for  conveying  milk  through  a  floor 

39  Cream  Cooler  connected  with  Separator 

40  Cream  Bottle  Filler 

41  Bottle  Carriers 

42  Car  for  conveying  Carriers  and  Bottles 

43  Car  for  conveying  Carriers  and  Bottles 

44  Wagon  Box  for  carrying  bottles  on  ice 

45  Star  Milk  Bottles 

46  Paper  Bottle  Filling  and  Capping  Machine  . 

47  Hand  Separator  for  separating  cream  from  milk  . 

48  Milk  Wagon 

49  Milk  Wagon         ....... 

50  Delivery  Basket  ....... 

51  Method  of  Marking  Parchment  Caps  for  Certified  Milk 

52  Copper  Case  for  Holding  Bottle  Caps  . 

53  Dipper  and  Siphon  for  Removing  Cream  from  Bottles 

54  Small  Babcock  Machine        ..... 

55  Eight-Bottle  Babcock  Machine     .... 

56  Small  Babcock  Machine        ..... 

57  Pipette  for  making  the  Babcock  test     . 

58  Shows  method  of  Using  Pipette  for  Babcock  Test 

59  Quevenne's  L,aetodensimeter         .... 


Page 


folk 


foil' 


LIST  OF  ILL  USTRA  TIONS 


follow 


Fig. 

60  Tubes  for  Hart's  Casein  Test 

61  Feser's  L,aetoseope        .... 

62  Collecting  Case  for  Milk  Samples 

63  Petri  Dishes  ..... 

64  Pipettes        ...... 

65  Petri  Dish  Showing  Colonies  of  Bacteria 

66  Counting  Box 

67  Filling  Test  Tubes  with  Culture  Medium 

68  Hardening  Agar  Slants 

69  Two  Burettes  arranged  for  Titrating  Culture  Media 

70  Platinum  Needles         .... 

7 1  Cutter  for  Making  Potato  Plugs  . 

72  Types  of  Surface  Elevation 

73  Types  of  Gelatin  Liquefaction     . 

74  Flasks  and  Vials  for  quantitative  bacteriological  analysis 

75  Yeksa  Sunbeam  (Guernsey) 

76  Shadybrook  Gerben  (Holstein)     . 

77  Pansy  of  Woodroffe  (Ayrshire)     . 

78  Loretta  D  (Jersey)        .... 

79  Showing  Stable  of  J.  D.  Farrell,  Esq. 

80  Sketch  of  Ground  Plan  of  Milk  House 
Si  Showing  Stable  of  J.  D.  Farrell,  Esq. 

82  Showing  Washroom  (J.  D.  Farrell,  Esq.) 

83  Showing  Milk  Room  (J.  D.  Farrell,  Esq.) 

84  Interior  of  the  Paulhamus  Barn  . 

85  Sketch  of  Ground  Plan  of  Barn  for  Forty  Cows  . 

86  Bottle  Washing  Machine  at  the  Paulhamus  Farm       follows 

87  Sketch  of  Ground  Plan  of  Milk  House         . 

88  Cement  Sterilizer  at  the  Paulhamus  Farm 

89  Side  and  Rear  View  of  Stall  of  Cow  Stable 

90  The  Improved  Drown  Stall  . 

91  Swing  Stanchion  and  Cross  Section  of  Feed  Trough     . 

92  Stall  with  Panel  Wooden  Floor    ...... 

93  Shows  a  Small  Dairy  House 

94  Floor  Plan  of  Small  Plant  for  Certified  Milk  Connected  with 

Barn   ........ 


Page 
201 
203 
252 
257 
258 
260 
261 
268 

273 
288 

297 
298 

299 
301 
308 


follow     316 


follows 


•  1 


follow 


follows 


322 
323 


follow     324 


325 

326 

327 
328 
330 
330 
332 

333 
333 


334 


LIST  OF  I L LUSTRA  TIONS 

Fig.  Page 

95  Floor  Plan  of  Creamery  and  City  Milk  Plant      .          .          .  334 

96  Front  Elevation  of  Creamery  and  City  Milk  Plant      .  -335 

97  Floor  Plan  of  Creamery  for  Whole  Milk     ....  335 

98  The  Burrell-Lawrence-Kennedy  Cow  Milker       .        follows  338 

99  The  Pulsator "  338 

100  Illustrating  the  Hegelund  Method  of  Milking    .  342 

101  Moak's  Card  for  Identifying  Cows 357 


CHAPTER  I 


GERMS  IN  THEIR  GENERAL  RELATIONS  TO  MILK 


THE  object  of  this  book  is  to  show  the  importance — nay, 
even  necessity — of  a  clean  milk  production,  and  the  prac- 
tical methods  by  which  it  may  be  obtained.  Heretofore 
milk  has  been  regarded  much  in  the  same  light  as  other 
articles  of  food,  but  it  differs  from  them  in  many  important  respects. 
It  is  the  only  animal  food  which  is  commonly  eaten  in  the  raw  state, 
and  it  forms  the  sole  diet  for  human  beings  at  an  immature  age, 
when  they  are  least  able  to  cope  with  the  disorders  which  con- 
taminated and  dirty  milk  is  liable  to  produce.  Again — and  this; 
is  the  chief  reason  why  milk  needs  especial  care  in  its  production — 
it  always  contains  more  or  less  germs,  and,  indeed,  forms  one  of 
the  most  favorable  foods  on  which  germs  grow. 

The  common  idea  of  germs  appears  to  be  that  they  are  chiefly 
important  in  being  the  cause  of  disease,  and  while  some  germs  do 
produce  disease — and  occasionally  those  inhabiting  milk  which  has 
not  been  properly  cared  for — yet  they  mainly  interest  the  farmer 
on  account  of  their  powerful  and  enormous  influence  upon  milk  and 
its  products.  The  chief  aim  of  this  book  is  to  enforce  on  the  farmer 
and  dairyman  this  one  fact,  that  the  One  Essential  in  producing 
and  handling  milk  is  Cleanliness,  and  cleanliness  means  in  this 
connection  freedom  from  germs,  so  far  as  this  is  possible.  It  would 
scarce  be  an  exaggeration  to  say  that  all  the  trouble  which  arises 


jffS$&» 


.2  CLEAN  MILK 

in  the  endeavor  to  secure  good  milk  or  milk-products  results  from 
the  contamination  of  milk  with  undesirable  germs.  Thus  the 
proper  taste,  odor,  color,  consistency  and  keeping  qualities  of  milk 
depend  upon  its  comparative  freedom  from  undesirable  germs. 
Conversely,  the  souring  of  milk  and  faults  in  odor,  color,  consist- 
ency and  taste  depend  almost  wholly  upon  the  presence  of  one  or 
more  varieties  of  germs. 

[Moreover,  the  prevention  of  contamination  of  milk  with  miscel- 
laneous germs  is  just  as  important  in  order  to  make  the  best  pro- 
ducts from  milk,  as  it  is  to  avoid  disease  in  man.  Thus  the  finest 
cream  is  only  produced  from  milk  in  which  germs  are  comparatively- 
absent.  Cream  laden  with  miscellaneous  germs  has  bad  keeping 
qualities  and  often  a  faulty  taste  or  odor.  Most  of  the  so-called 
faults  of  butter  arise  not  from  improper  feeding  of  cows  or  from 
improper  making  or  handling  of  butter,  but  from  undesirable  germs 
Which  infest  it.  Among  some  of  the  more  common  faults  of  butter 
are  poor  flavor,  tallowy  or  oily  butter,  butter  having  a  bitter,  rotten 
or  root-taste  like  turnips,  rancid,  mottled  and  moldy  butter,  and 
butter  of  unusual  colors;  all  of  these  faults  have  been  proved  to  be 
due  to  the  contamination  of  butter  with  germs  which  existed  in  the 
milk. 

"While  germs  in  milk  produce  changes  in  cheese  which  give  rise 
to  its  proper  consistency  and  flavor,  yet  it  is  only  a  certain  type  or 
types  of  germs  which  are  desirable,  and  a  general  pollution  of  milk 
with  germs  of  many  kinds  may  wholly  unfit  milk  for  cheese  making. 

It  is  essential  that  milk  should  be  pure  when  employed  for 
condensing,  and,  although  germs  are  destroyed  in  the  process,  this 
is  much  more  readily  accomplished  if  the  milk  is  clean  in  the  begin- 
ning" and  the  keeping  qualities  will  be  much  better.  Above  all, 
when  milk  is  sold  for  general  consumption  it  must  be  pure — com- 
paratively germ- free — to  be  wholesome,  to  bring  a  good  price,  to 
keep,  and  to  fall  within  the  legal  requirements  which  will  soon 
become  general  throughout  this  country. 


GERMS  IN  RELATION  TO  MILK  3 

Heretofore,  when  milk  was  regarded  in  the  same  light  as  any 
other  food,  the  law  required  simply  that  it  should  not  be  adulterated 
and  that  it  should  contain  a  quantity  of  food-constituents  equivalent 
to  the  minimum  standard  in  force.  Now,  however,  it  has  come  to 
be  realized  that  of  the  two  the  cleanliness  of  the  milk  is  an  hundred- 
fold more  important  than  its  food  value.  While  a  milk  poor  in 
fat  may  mean  a  certain  loss  of  nutriment  to  one  using  it,  the  con- 
tamination of  milk  with  certain  germs  may  be  a  matter  of  life  and 
•death  to  the  consumer — particularly  if  an  infant.  The  sooner  the 
farmer  and  dairyman  realize  that  the  secret  of  success  in  the  making 
of  milk  and  milk-products  is  cleanliness — and  by  cleanliness  we 
mean  essentially  methods  to  prevent  the  entrance  of  germs  into 
milk — the  better  will  it  be  for  them  and  for  everyone. 

Germs,  or,  as  they  are  more  technically  termed,  bacteria,  are 
the  most  minute  forms  of  plant  life  we  know.  They  occur  in  vari- 
ous shapes,  but  chiefly  in  the  form  of  either  rods,  round  cells  or 
spirals.  When  seen  through  the  microscope  they  present  some- 
what the  appearance  of  minute  lines,  balls  or  cork-screws,  accord- 
ing as  they  belong  to  one  or  the  other  of  these  three  types.  In 
masses  of  thousands  they  may  be  visible  to  the  naked  eye  as 
specks  like  mold,  but  singly  they  can  only  be  seen  with  a  compound 
microscope  magnifying  more  than  500  times.  The  most  common 
of  all  varieties  of  germs  in  milk  are  those  which  cause  it  to  sour — 
the  lactic  acid  bacilli  (the  bacilli  are  the  rod  or  shaped  germs), 
and  these  are  about  3-25,000  of  an  inch  long  and  1-25,000  of 
an  inch  broad.  Germs  grow  on  vegetable  and  animal  matter, 
but  not  in  the  tissues  or  cells  of  living  animals  or  vegetables,  al- 
though they  are  found  on  all  parts  of  them  exposed  to  the  air. 
Germs  are,  in  fact,  everywhere — in  the  air,  in  water,  in  soil,  on  the 
skin  and  in  the  digestive  canal  of  animals  and  on  the  surface  of 
plants  and  in  dust.  Professor  Conn  has  found  as  many  as  200 
different  kinds  of  germs  in  milk  alone.  Germs  propagate  by 
dividing   into   two   equal   parts — more   usually — which    form   new 


4  CLEAN  MILK 

individuals.     The  time  required  for  a  germ  to  mature  and  form  el 
new  germ  may  not  be  more  than  twenty  minutes. 

Germs  also  multiply  by  spores — that  is,  small,  round  or  egg- 
shaped  bodies  appear  within  the  mature  germ  and  these  later 
break  loose  and  develop,  under  favorable  circumstances,  into  full- 
grown  germs  again.  Germs  which  increase  in  this  manner  are 
much  more  difficult  to  kill,  for  in  the  spore  stage  they  often  defy 
prolonged  heat,  even  at  the  boiling  temperature,  and  also  cold  at 
or  below  freezing  and  dryness,  as  dust,  in  which  they  may  exist  for 
years.  To  show  the  possibilities  in  the  way  of  multiplication,  it  has 
been  calculated  that  a  single  germ,  under  favorable  circumstances, 
may  within  twenty-four  hours  produce  over  sixteen  millions  of 
progeny. 


General  shape  of  bacteria,     a,  spheres;  b,  rods;  c,  spirals.     (After  Conn.) 


Germs,  however,  depend  upon  certain  conditions  for  their 
growth;  otherwise  they  would  crowd  all  other  life  off  the  globe. 
Besides  organic  matter  to  feed  on,  the  chief  circumstances  limiting 
their  existence  are  heat  and  moisture.  Germs  usually  do  not  grow 
at  a  temperature  below  390  or  above  1400  F.  This  does  not  apply 
to  the  growth  of  bacteria  in  ice  cream,  as  germs  may  multiply  five- 
fold within  three  days  in  ice  cream  kept  at  a  temperature  five  de- 
grees below  zero  Fahrenheit.  Milk  kept  frozen  at  29°-3i°  F.,  con- 
taining but  a  few  hundred  bacilli  to  the  cubic  centimeter  at  the  begin- 
ning, may  contain  hundreds  of  millions  of  germs  when  kept  in  cold 
storage  at  this  temperature  after  5  or  6  weeks  (Pennington).  The 
milk  at  the  end  of  this  period  is  not  altered  in  odor,  taste  or  in  any 
way  to  show  the  tremendous  germ-contamination. 


GERMS  IN  RELATION  TO  MILK  5 

It  does  not  even  curd  on  heating.  The  proteids  of  the  milk  are, 
Trowever,  transformed  into  cleavage  products  owing  to  digestion  of 
the  casein  by  the  peptonizing  or  digestive  action  of  the  bacteria. 

Such  decomposed  milk  may  be  harmful  or  actually  poisonous, 
and  all  milk  kept  sweet  over  long  periods  by  cold  alone  is  to  be  re- 
garded as  unfit  for  food — especially  for  infants. 

The  number  of  germs  developing  in  milk  at  the  freezing  temper- 
ature is  considerably  greater  than  in  milk  kept  at  room  or  body 
temperatures  after  the  elapse  of  several  weeks.  Freezing,  therefore, 
does  not  necessarily  destroy  germs — as,  for  instance,  the  germs  of 
typhoid  fever  have  remained  alive  in  ice  for  a  period  of  three  months 
— but  this  temperature  retards  their  growth  (see  p.  6)  and  many 
kinds  of  germs  are  killed  by  it.  Ice  water  is  therefore  compara- 
tively free  from  germs.  The  most  favorable  temperature  for  the 
.growth  of  disease  germs  is  that  of  the  animal  body — from  980  F. 
to  1030  F. — while  most  other  germs  multiply  most  readily  between 
the  temperatures  of  590  F.  and  yy°  F. 

This  knowledge  is  of  the  greatest  importance  in  the  care  of 
milk  and  teaches  us  that  the  chief  essential  consists  in  cooling  it 
immediately  to  a  low  temperature  (400  F.  to  500  F.)  and  keeping 
it  at  this  temperature  thereafter  till  consumed.  The  number  of 
.germs  in  milk  is  always  estimated  as  that  number  contained  in  a 
■cubic  centimeter  of  milk.  A  cubic  centimeter  represents  a  cube 
holding  a  quantity  of  liquid  equivalent  to  about  one-quarter  of  a  tea- 
:spoonful,  or  sixteen  drops  of  water.  If  very  clean  milk  is  kept  below 
500  F.  for  24  hours  there  is  not  only  not  an  increase  but  generally  a 
decrease  in  the  number  of  germs,  and  the  same  usually  holds  good 
for  very  clean  milk  kept  36  hours  below  45  °  F.  The  initial  decrease 
in  the  number  of  germs  in  new  milk  is  due  to  a  feeble  and  variable 
germ-destroying  substance  present  in  fresh  milk.  Immediate  cool- 
ing does  not  affect  the  germicidal  substance,  but  heating  milk  may 
destroy  it  (see  p.  10).  The  bactericidal  body  in  milk  does  not  lower 
the  number  of  bacteria  in  milk  which  is  kept  at  high  temperatures — 


6  CLEAN  MILK 

over  6o°  F.  The  germicidal  action  disappears  spontaneously  in  old 
milk.  After  36  hours,  when  milk  is  kept  at  400  F.,  there  is  an 
increase  in  the  number  of  germs.  Dr.  Park  found  in  a  sample  of 
milk  containing  only  3,000  germs  in  the  cubic  centimeter,  that  after 
24  hours  at  420  F.  it  contained  2,600  germs;  after  48  hours  3.600 
germs ;  and  after  96  hours  500,000  germs  to  the  cubic  centimeter. 
The  bacteria  in  reasonably  clean  milk  (12,000  to  25,000  per  c.c.) 
will  multiply  some  fourfold  at  500  F.  in  24  hours;  and  at  about  the 
same  rate  when  kept  at  460  F.  for  36  hours.  The  number  of  germs- 
in  milk  kept  at  32 °  F.  lessens  from  day  to  day  for  a  number  of 
days,  then  increases. 

When  milk  is  kept  at  higher  temperatures  the  germs  multiply 
rapidly  and  it  sours  and  deteriorates  correspondingly.  It  has  been 
shown  that  very  clean  milk  ( containing  but  3,000  germs  to  the 
cubic  centimeter),  if  kept  for  24  hours  at  6o°  F.,  held  180,000 
germs;  if  kept  at  86°  F.  for  24  hours  it  contained  1,400,000  germs;; 
and  at  940  F.  the  germs  multiplied  so  tremendously  that  at  the  end 
of  24  hours  the  same  milk  contained  25  billion  germs  per  cubic 
centimeter. 

All  germs  require  some  moisture  in  order  that  they  may" 
actually  grow,  but  they  may  exist  in  large  quantities — for  a  longer 
or  shorter  time — in  dust.  Some  require  air  for  their  existence,, 
others  do  not. 

Sunlight  is  one  of  the  most  powerful  enemies  of  germs,  since 
few  will  thrive  in  sunlight,  especially  in  the  presence  of  fresh 
air.  This  explains  the  value  of  sunning  dairy  utensils  and  of  per- 
mitting the  sunlight  to  enter  freely  into  the  barn  and  dairy.  Some 
germs  grow  more  readily  in  substances  having  an  alkaline  or  neutral 
reaction ;  others,  as  those  which  cause  milk  to  sour,  flourish  in  an. 
acid  medium,  providing  the  acidity  is  not  too  great. 

The  most  potent  factors  in  destroying  germs  are  intense  heat 
and  cold,  sunlight  and  chemicals.  A  temperature  varying  from 
1400  to  1580  F.  will  kill  most  germs — if  continued  long  enough  or 


GERMS  IN  RELATION  TO  MILK  7 

repeated  at  frequent  intervals.  Milk  treated  by  continued,  inter- 
mittent heating  at  1400  F.  has  been  kept  for  years  without  chang- 
ing, owing  to  the  destruction  of  germs  (and  ferments)  in  it.  As 
the  time  required  for  the  destruction  of  germs  at  this  temperature 
is  too  great  for  commercial  purposes,  temperatures  ranging  from 
1600  to  1760  F.  are  usually  applied  for  either  killing  or  checking 
the  development  of  germs  in  milk.  Heating  milk  below  the  boiling 
point  with  this  object  in  view  is  called  technically  pasteurization, 
after  the  great  originator  of  the  process.  If  properly  done,  pasteur- 
ization kills  most  of  the  germs  in  milk  (95  to  98%  of  all  bacteria, 
including  those  which  cause  disease  in  the  human  most  commonly, 
t.  e.,  the  miscellaneous  and  undetermined  germs  which  induce  diar- 
rheal diseases  in  infants,  and  the  special  germs  of  typhoid  and  scarlet 
fever,  malta  fever,  tuberculosis,  and  diphtheria),  and  this  is  the  best 
way  to  obviate  the  dangers  of  dirty  milk  for  human  consumption — 
more  particularly  in  the  case  of  infants.  The  spores  of  germs — 
the  immature  forms  from  which  germs  develop — are  not  killed  by 
pasteurization  or  even  by  boiling  milk ;  a  still  higher  temperature 
is  required.  Most  milk  contains  some  spore-bearing  germs  and  so 
cannot  be  made  absolutely  germ-free  by  pasteurization  or  boiling. 
Boiling  milk  alters  its  taste  and  chemical  composition,  and  renders 
it  somewhat  less  digestible.  There  are  certain  drawbacks  to  pas- 
teurization, however.  If  the  milk  has  been  kept  long  before  heat- 
ing, poisons  may  form  in  it  which  the  heat  will  not  destroy. 

Our  knowledge  concerning  these  poisons  (or,  more  technically, 
toxins)  resulting  from  the  growth  of  germs  is  very  slight.  That  is, 
concerning  the  varieties  of  germs  which  may  produce  toxins  in  milk, 
and  the  harm  which  they  do,  and  the  effect  of  heat  upon  them.  It 
is  generally  conceded,  however,  that  it  is  impossible  to  make  an  old 
and  dirty  milk  harmless  by  heating  it,  and  that  myriads  of  dead 
bodies  of  germs  and  their  products  are  sometimes  poisonous  to 
infants — even  after  the  milk  containing  them  has  been  pasteurized. 
Milk,  then,  which  contains  a  large  number  of  germs,  or  an  acidity 


8  CLEAN  MILK 

over  0.2%,  is  unfit  for  pasteurization.  A  high  acidity  generally 
means  an  excess  of  spore-bearing  germs  which  are  not  killed 
by  pasteurization.  These  induce  putrefactive  changes  in  milk  with 
the  production  of  poisons  or  ptomaines  from  decomposition  of  the 
milk — not  directly  from  the  growth  of  germs.  Milk  and  cream 
should,  then,  be  pasteurized  when  fresh,  since  when  old  the  spore- 
bearing  germs  are  apt  to  be  abundant.  Commercial  pasteurization 
is  therefore  more  fitly  done  in  the  country  at  the  creamery. 

There  are  certain  substances  naturally  present  in  cows'  milk 
exactly  resembling  those  which  bring  about  the  digestion  of  food  in 
the  stomach  and  bowels  of  man  and  animals.  These  chemical  sub- 
stances in  milk  or  in  the  digestive  organs  are  called  ferments  (or 
enzymes).  They  appear  to  aid  the  digestibility  of  milk,  particularly 
in  infants,  and  are  destroyed  by  heating  milk  over  1500  F.,  or  at  a 
lower  temperature  if  the  milk  is  repeatedly  heated.  These  natural 
ferments  in  milk  one  must  keep  distinct  in  the  mind  from  those 
ferments  formed  by  germs  accidentally  contaminating  milk  (see 
below).  It  is  generally  accepted,  however,  that  babies  will  not 
thrive  so  well  on  pasteurized  milk  for  long  periods,  as  on  clean,  un- 
heated  milk,  and  occasionally  develop  malnutrition,  anemia,  rickets 
and  scurvy.  The  last  may  be  prevented  by  feeding  infants  one 
tablespoonful  of  orange  juice  twice  daily.  It  is  known  that  scurvy 
in  infants  sometimes  occurs  in  infants  fed  on  breast  milk  and  on 
raw  cows'  milk.  I  have  had  a  case  in  my  own  practice  in  a  breast- 
fed baby.  The  milk  was  very  low  in  fat  ( 1.55% )  and  probably  also 
in  proteids. 

Moreover,  it  has  been  contended  that  pasteurized  milk  is  more 
digestible  than  unheated  milk,  since  heating  milk  prevents  the  fat 
globules  from  running  together,  and  since  heating  lessens  the  curd- 
ling of  milk  in  the  stomach  by  rennin.  The  same  effect  is  seen  out- 
side the  body  in  the  action  of  rennet  on  raw  and  heated  milk.  Fin- 
ally, there  are  experiments  that  seem  to  show  that  pasteurized  milk 
is  absorbed  more  readily  than  raw  milk  from  the  bowels. 


GERMS  IN  RELATION  TO  MILK  g 

It  may  be  positively  affirmed,  however,  that  American  phy- 
sicians having  most  experience  and  knowledge  of  feeding  babies 
are  generally  agreed  that  infants  thrive  best  on  clean,  unheated 
milk. 

The  whole  question  of  the  comparative  value  of  raw  and 
pasteurized  milk  for  infants'  food  is  still  undecided.  In  either  case 
it  is  equally  imperative  that  the  milk  be  as  clean  as  possible. 

The  "  ferments  "  of  milk  aid  digestion  of  milk,  and  even  that  of 
other  food  taken  with  the  milk.  Different  ferments  occur  in  the 
milk  of  different  animals.  Similar  ferments  occur  in  the  milk  of 
women  and  bitches ;  also  there  are  like  ferments  in  the  milk  of  cows 
and  goats. 

Besides  the  ferments  in  fresh  milk,  there  is  also  a  body  which  is 
destructive  to  germs.*  It  is  probable  that  both  the  ferments  and 
this  germicidal  substance  disappear  spontaneously  in  24  hours,  and 
"both  are  weakened  or  destroyed  by  high  degrees  of  heat.  The  chief 
ferments  in  cows'  milk  are  the  following:  1.  Galactase.  This  is  a 
proteolytic  ferment,  or  that  digesting  proteids,  as  casein  of  milk. 
Other  proteids  in  the  stomach  may  be  digested  to  some  slight  extent 
by  it  in  new  milk.  Galactase  occurs  in  the  milk  of  most  animals  and 
is  not  destroyed  except  by  heat  near  the  boiling  point.  Galactase 
consists  of  galactase  proper  and  two  other  ferments  (catalase  and 
peroxidase),  which  do  not  affect  the  digestion  of  milk.  2.  Lipase. 
This  is  a  fat-splitting  or  fat  digesting  ferment.  It  is  weakened  by 
a  temperature  of  145  °  F..  and  destroyed  by  1490  F.  3.  Lactokinasc. 
This  digests  proteids  similarly  to  galactase,  but  acts  especially  in 
the  small  intestines  of  animals  consuming  milk.     It  is  destroyed  by 


*  It  should  be  stated,  however,  that  Stocking  denies  that  there  is  any  germi- 
cidal substance  in  milk.  From  his  experiments  he  concludes  that  the  primary- 
decrease  in  bacterial  content  in  fresh  milk  is  simply  due  to  dying  out  of  those 
varietiesof  bacteria  which  do  not  readily  flourish  in  milk.  If  bacteria — which  find 
in  milk  their  natural  habitat— predominate  in  fresh  milk,  then  there  is  a  constant 
increase  from  the  time  the  milk  is  drawn.  These  bacteria  natural  to  milk  include 
the  B.  lactis  acidi  and  B.  lactis  aerogenes. 


io  CLEAN  MILK 

heat  from  1630  F.  to  1670  F.  The  germ-destroying  substance  is 
weakened  by  1490  F.,  acting  for  half  an  hour. 

Now,  the  important  point  lies  in  the  fact  that  the  disease  germs 
which  occasionally  are  present  in  milk  (germs  of  typhoid  and  scarlet 
fever,  diptheria,  tuberculosis,  cholera  and  streptococci  and  staphy- 
lococci) may  be  killed  by  a  comparatively  low  degree  of  heat  (1400 
F.)  without  destruction  of  either  the  ferments  or  the  germ  destroy- 
ing substance. 

Then  there  may  be  the  poisons,  spoken  of  above,  to  be  con- 
sidered. Those  arising  in  milk  from  germ  growth  (toxines)  we 
have  little  knowledge  of,  but  those  we  do  know  about  (as  the  toxines 
of  diphtheria  and  tetanus)  are  readily  destroyed  by  a  low  degree  of 
heat  (1400  F.)  The  poisons  or  ptomaines  arising  from  the  action 
of  spore-bearing  germs  in  causing  putrefaction  of  old  milk  are 
found  in  pasteurized  milk  because  heat  does  not  kill  these  germs. 
From  what  has  been  said  it  would  seem  that  the  temperature  of 
1400  F.  is  most  suitable  for  heating  milk  intended  for  infant  food. 
The  time  during  which  milk  should  be  thus  heated  has  been  found 
(Freeman)  to  be  30  minutes  in  order  to  effectively  kill  most  germs. 

This,  then,  seems  the  best  temperature  and  time  for  pasteuriz- 
ing milk  for  infant  food.  Milk  is  more  commonly  pasteurized  now 
at  higher  temperatures.  To  be  effective  in  killing  germs  pasteur- 
ization should  be  done  as  follows:  If  milk  is  heated  to  1500  F., 
it  should  be  maintained  at  this  point  for  20  minutes;  if  to  1600  F., 
then  it  should  be  maintained  for  15  minutes;  if  to  1700  F.,  then  it 
should  be  maintained  for  10  minutes.  As  a  matter  of  fact,  most 
medical  authorities  have  been  in  the  habit  of  pasteurizing  milk  for 
infants  at  1500  F.  to  1600  F.  for  20  minutes.  Authorities  differ 
somewhat  as  to  the  proper  pasteurizing  temperature.  Pasteurizing 
at  a  low  temperature  (1400  F.)  is  chiefly  important  for  infants — 
not  for  adults.  Park  states  that  heating  milk  at  the  following  points 
will  kill  typhoid,  tubercle  and  other  non-spore  bearing  organisms : — 

For  10  minutes  at  8o°  C.  (1760  F.). 


GERMS  IN  RELATION  TO  MILK  n 

For  15  minutes  at  70  °  C.  (1580  F.). 

For  1  minute  at  700  C.  kills  99%  of  tubercle  bacilli  (tubercu- 
losis germs)  and  95-98%  of  other  non-spore  bearing  germs. 

Rosenau  finds  milk  heated  to  6o°  C.  (1490  F.)  for  20  minutes 
kills  tubercle  bacilli  and  Malta  fever  germs;  for  10  minutes — dys- 
entery bacilli;  for  2  minutes — typhoid,  diphtheria  and  cholera  or- 
ganisms. 

"  Ferments,"  or  enzymes,  must  be  distinguished  from  germs  (or 
living  ferments),  which  are  the  most  common  causes  of  fermenta- 
tion. Enzymes  are  chemical  substances,  but  are  derived  from  liv- 
ing cells. 

Those  related  to  milk  are  derived  from  three  sources.  1.  They 
may  naturally  exist  in  milk  and  are  presumably  secreted  by  the 
udder  cells,  as  rennet  is  secreted  by  the  stomach.  The  ferments  just 
described  belong  to  this  class.  2.  They  may  be  produced  by  various 
germs  contaminating  milk  (as  the  rennet-like  ferment  of  certain 
germs;  the  liquefying  ferments  of  liquefying  or  putrefactive  bac- 
teria). 3.  The  third  class  includes  simply  rennet  obtained  from  the 
animal  stomach  and  often  added  artificially  to  milk  in  cheese- 
making,  etc. 

There  is,  indeed,  as  much  difference  in  practice  as  in  theory  re- 
garding the  comparative  value  of  heated  and  raw  milk  for  infant 
feeding — even  in  the  case  of  certified  milk.  Thus  in  nine  milk 
stations  (see  p.  173) supplying  milk  for  babies  in  different  cities  of 
this  country,  under  the  best  medical  supervision,  we  find  that  the 
practice  of  four  stations  is  to  feed  the  certified  milk  raw  as  it  comes 
from  the  dairy;  in  three  the  certified  milk  is  wholly  pasteurized; 
and  in  two  stations  the  certified  milk  is  under  some  circumstances 
pasteurized  (as  in  hot  weather).  It  remains  to  be  seen  whether 
milk  heated  to  1400  F.  will  be  deficient  in  any  properties  of  fresh, 
unheated  milk. 

Obstinate  constipation  is  sometimes  seen  in  animals  and  chil- 
dren living  on  milk  pasteurized  at  the  higher  temperatures.     In  the 


12  CLEAN  MILK 

public  use  of  pasteurized  milk*  there  arises  the  difficulty  of  determin- 
ing its  true  condition  by  ordinary  tests  at  our  command.  Thus  it 
may  not  show  acidity  when  old  (as  lactic  acid  germs  are  most 
readily  killed  by  heat),  nor  may  it  be  altered  in  appearance  or  taste, 
and  yet  be  swarming  with  deleterious  germs — if  kept  for  some  time 
at  low  temperature. 

These  last  remarks  apply  particularly  to  pasteurized  milk  which 
has  been  insufficiently  heated  (  not  una  immonly  so  in  commerce  as 
regards  time  of  heating),  or  which  has  been  placed  in  dirty  or  un- 
sealed containers,  or  to  that  which  has  not  been  rapidly  cooled,  or 
to  that  which  was  too  dirty  and  germ-laden  before  heating,  or  to 
milk  kept  too  long  after  heating.  Therefore  it  will  be  seen  that 
pasteurization  will  not  make  a  dirty  or  old  milk  harmless,  and 
that  the  same  care  in  cooling,  in  the  use  of  clean  utensils,  in 
avoidance  of  contamination  in  handling,  together  with  the  necessity 
for  its  speedy  consumption,  are  as  essential  as  with  clean,  unheated 
milk. 

Against  all  objections  to  pasteurized  milk  the  one  salient,  un- 
deniable fact  stands  out,  viz.,  that  properly  pasteurized  milk  is  a 
comparatively  safe  food,  whereas  unheated  milk  is  not.  This  fol- 
lows because  occasionally  in  the  most  carefully  handled  certified 
milk  contamination  with  contagious  disease  may  occur,  while  in 
ordinary  market  milk  not  only  is  this  danger  present,  but  that  of 
tuberculosis  germs,  and  the  many  miscellaneous  bacteria  arising 
from  manure,  filth,  impure  water  and  utensils  and  disease  of  cows. 
But  since  the  chance  of  harm  from  certified  milk  is  slight,  and  be- 
cause of  objections  noted  regarding  pasteurized  milk  generally, 
Melvin  has  offered  the  following  solution.  He  advises  that 
all  market  milk,  except  such  as  is  "  certified  "  or  "  inspected,"  be 
subjected  to  compulsory  pasteurization  under  the  supervision  and 
control  of  health  authorities  (see  p.    186) 


For  municipal  regulations  of  pasteurized  milk  see  p.  21^. 


GERMS  IN  RELATION  TO  MILK  13- 

The  simplest  method  of  home  pasteurization  consists  in  bring- 
ing water  to  the  boiling  point  in  the  outer  part  of  a  double  boiler. 
As  much  water  should  be  used  as  can  be  contained  in  the  outer  part 
when  the  inner  part  of  the  double  boiler  is  in  place.  When  the 
water  boils,  the  outer  part  of  the  double  boiler  is  taken  off  the  fire 
and  placed  upon  a  piece  of  board.  Then  into  the  inner  part  is  placed 
the  milk  and  the  inner  part  is  inserted  into  the  outer  part  of  the 
double  boiler  and  is  covered.  After  the  milk  has  been  in  the  boiler 
20  minutes  the  inner  part  is  placed  in  cold  water.  It  should  then 
be  put  on  ice  and  covered.  Or  water  may  be  brought  to  the  boiling 
point  in  a  pot  having  a  close-fitting  cover.  Then  the  pot  is  at  once 
removed  from  the  stove  and  placed  on  a  board.  The  individual 
nursing  bottles,  having  been  previously  filled  with  milk,  are  now 
placed  in  the  pot  of  boiling  water,  which  is  covered.  The  water 
should  be  of  sufficient  depth  to  reach  the  same  level  without  the 
bottles  as  the  milk  reaches  within  them.  The  bottles  are  kept  in 
the  hot  water  for  20  minutes  and  then  cooled  in  cold  water  and 
kept  on  ice.  By  either  method  of  pasteurizing  the  milk  is  brought 
to  about  1650  F.  Freeman's  pasteurizer  is  to  be  commended  for 
more  accurate  results. 

Home  pasteurization  is  far  preferable  to  commercial  pasteuriza- 
tion, as  the  latter  is  at  present  not  at  all  to  be  relied  upon.  All  milk, 
not  certified  or  equivalent  to  certified  milk,  should  be  pasteurized 
for  use  by  infants  or  invalids.  Even  certified  milk  is  often  pasteur- 
ized when  employed  for  babies  and  the  sick.  In  the  summer  months 
this  may  be  advisable  and  in  New  York  at  the  Straus  milk  stations 
certified  milk  is  pasteurized  the  year  round. 

As  I  have  observed,  in  pasteurization  done  on  a  large  scale  for 
market  purposes  in  Seattle,  the  result  has  been  a  farce  other  than  it 
enabled  the  milkman  to  keep  the  milk  for  perhaps  twenty-four  hours 
longer  than  it  would  have  otherwise  kept  sweet.  The  pasteurization 
of  the  market  milk  is  done  for  one  to  three  minutes  in  machines  of 
the  continuous  type.     The  pasteurizers  having  a  large  chamber,  in 


14  CLEAN  MILK 

which  the  milk  may  be  retained  for  the  required  time,  at  the  proper 
temperature,  are  preferable. 

Almost  all  the  commercial  pasteurizers  are  of  the  continuous 
type,  for  convenience  in  handling  large  quantities  of  milk,  and  are 
made  to  allow  milk  to  flow  through  them  as  quickly  as  possible, 
after  the  temperature  of  the  milk  has  been  raised  to  1550  F., 
165  °  F.,  or  thereabouts.  A  discontinuous  pasteurizer,  in  which  the 
milk  is  heated  by  a  hot  water  jacket  while  it  is  kept  in  motion  by 
rotating  arms  or  other  device,  is  to  be  preferred  because  the  milk 
may  be  kept  in  the  machine  for  the  proper  time  after  it  has  reached 
the  desired  temperature. 

When  milk  is  to  be  used  directly  for  food  it  is  better  that  it 
be  pasteurized  in  sterile  bottles  so  that  it  may  not  become  afterward 
contaminated  by  handling. 

The  bottles  are  first  cleaned  and  sterilized,  and  filled  and 
capped,  and  then  placed  in  a  steam  sterilizer;  or  are  immersed  to 
their  necks  in  a  water  bath  heated  by  steam.  All  milk  should  be 
rapidly  cooled  after  pasteurization.  If  in  bottles,  the  water  about 
the  bottles  is  quickly  reduced  in  temperature.  If  milk  is  heated  and 
unstirred  in  open  vessels  a  scum  will  form  on  the  surface  in  which 
the  germs  of  tuberculosis  may  not  be  killed  by  ordinary  pasteuriza- 
tion temperature  and  time.  The  cost  of  pasteurization  is  said  to 
be  from  1/10  to  l/2  cent  per  quart.  Rapid  alteration  in  temperature 
is  particularly  effective  in  killing  bacteria.  So  that,  in  the  short 
pasteurization  done  commercially,  rapid  cooling  is  of  the  greatest 
import.  Rapid  cooling  also  destroys  the  cooked  taste  of  milk. 
Pasteurized  milk  should  not  only  be  immediately  cooled  to  400  F., 
after  heating,  but  should  be  kept  at  that  temperature  in  closed,  ster- 
ilized bottles  or  cans  for  several  hours  before  it  is  delivered — to 
still  further  check  the  growth  of  bacilli. 

In  order  that  a  pasteurizer  shall  fulfil  the  scientific  require- 
ments it  must  be  able  to  heat  the  entire  amount  of  milk  it  contains 
(including  the  froth)  to  the  proper  temperature,  and  maintain  the 


GERMS  IN  RELATION  TO  MILK  15 

milk  at  this  temperature  for  the  time  suitable  to  the  temperature. 
Also  the  machine  must  work  reliably  and  be  easy  to  clean.  Com- 
mercial pasteurizers  should  also  have  an  automatic,  temperature- 
regulating  device  which  is  self-registering,  and  this  is  now  de- 
manded by  Boards  of  Health  (p.  217). 

Imperfect  pasteurization  prevents  milk  from  souring  quickly 
because  the  germs  which  cause  milk  to  sour  are  those  most  readily 
succumbing  to  heat  (since  they  are  generally  not  spore-bearing 
germs).  The  general  effect  of  imperfect  pasteurization  is  simply  to 
check — for  a  longer  or  shorter  time — the  growth  of  germs.  They 
are  retarded  in  their  development,  not  killed.  Disease  germs  may 
not  be  wholly  destroyed  in  the  process.  Experiments  which  I  have 
conducted  with  the  pasteurized  milk  of  the  general  market  (in  cans) 
showed  that  while  containing  but  15,000  germs  to  the  cubic  centi- 
meter, soon  after  emerging  from  the  pasteurizer  on  the  delivery 
wagon,  in  twenty-four  hours  the  same  milk  contained  several  million 
germs  to  the  cubic  centimeter.  Drs.  Bergey  and  Pennington  found 
much  the  same  result  in  Philadelphia ;  that  raw  and  recently  pasteur- 
ized milk  contained  respectively  1,260  and  12  bacteria,  but,  at  the 
end  of  72  hours,  the  numbers  were  17,000,000  and  148,000,000 
germs.  Also  the  harmless  lactic  acid  germs  of  raw  milk  are  killed  by 
heat,  and  the  more  dangerous  germs  from  dirty  bottles,  corks  and 
dust  contaminate  the  improperly  pasteurized  milk.  A  commercial 
pasteurizer  which  fulfils  the  scientific  requirements  for  heating  milk, 
i.  e.,  one  in  which  milk  may  be  heated  to  a  given  temperature  and 
held  at  that  point  for  a  given  time,  is  the  Willmann  Perfect  Pasteur- 
izer made  by  the  Dairy  Machinery  and  Construction  Co.,  of  Shelton, 
Conn.  In  this  machine  the  milk  is  first  heated  to  145  °  F.  and  then 
passes  into  an  automatic  holding  machine,  where  it  is  maintained 
at  this  temperature  by  an  automatic  device  for  30  minutes,  when 
it  is  discharged  automatically  back  into  the  original  regenerative 
pasteurizer  and  thence  on  to  a  cooler  to  be  cooled  to  380  or  400  F. 
If  pasteurization  is  done  thoroughly  the  lactic  acid  bacilli   (sour 


1 6  CLEAN  MILK 

milk  germs)  are  destroyed  and  so  the  milk  does  not  sour  but  putre- 
fies when  it  ages. 

Pasteurization  prevents  milk  from  being  properly  curdled  by 
rennet  and  so  unfits  milk  for  cheese-making.  Cheese  is,  however, 
now  being  made  from  pasteurized  milk  to  which  is  added  a 
"  starter."  Pasteurized  milk  or  cream  may  be  used  to  advantage 
for  butter-making  when  the  lactic  acid  germs  are  added  in  the  form 
of  sour  milk,  known  as  a  "  starter,"  which  will  be  described  later. 
Since  butter  frequently  contains  tubercle  bacilli  (tuberculosis 
germs)  it  should  always  be  made  from  cream  derived  from  tuber- 
culosis-free cows  or  else  cream  should  be  properly  pasteurized.  If 
we  must  have  dirty  milk,  pasteurization  is  the  best  remedy  for  this 
unhappy  state  of  affairs,  but  it  may  well  prove  undesirable  to  thus 
remove  the  incentive  to  dairymen  to  produce  clean  milk.  If  done 
at  all  for  the  market,  it  should  be  done  thoroughly  (see  pp.  217-19), 
followed  by  rapid  cooling.*  If  milk  is  nut  cooled  down  to  allow 
point  after  pasteurization,  spores  will  develop  which  have  escaped 
destruction  on  account  of  their  great  resistance  to  heat,  and  these 
will  result  in  germs  which,  while  not  souring  milk,  act  on  the  casein 
to  cause  it  to  curdle  and  perhaps  become  poisonous  and  putrid. 
In  Europe  pasteurization  of  milk  is  much  more  common  than  in 
this  country,  since  ice  is  in  less  common  use.  In  Denmark  it  is 
required  by  law,  so  that  tuberculosis  may  not  be  spread  when  skim 
milk  and  buttermilk  are  returned  from  the  creameries  and  fed  to 
calves  and  pigs.  This  custom  should  be  imitated  in  the  United 
States,  since  the  young  stock  are  not  only  protected  from  disease, 
but  the  keeping  quality  of  the  skim  milk  is  so  much  improved.  A 
higher  temperature  than  1650  F.  gives  the  milk  a  boiled  taste  and 
alters  its  composition  to  some  extent.  Steam  or  boiling  water  are 
used  to  destroy  germs  in  or  on  dairy  utensils. 


*  Pasteurized  milk  which  is  sold  for  general  consumption  should  be 
always  marked  as  such,  in  order  that  infants  shall  not  be  harmed  by  its  use. 
(See  p.  1S7.) 


GERMS  IN  RELATION  TO  MILK  17 

Chemicals  find  little  use  as  germ-destroyers  in  a  properly  con- 
ducted dairy  or  farm.  They  may  be  employed  to  some  extent  in 
the  barn  (as  lime  scattered  on  the  floor),  or  in  case  milk  products 
become  faulty  through  some  contamination  with  special  germs  in 
the  stable  or  dairy,  and  in  case  the  stable  has  been  inhabited  by 
cows  having  tuberculosis,  when  general  disinfection  is  in  order 
(see  p.  346).  Various  preservatives  under  the  trade  names  of  Free- 
zine,  Iceline,  Preservaline,  Milk  Sweet  (all  containing  from  two  to 
five  per  cent,  of  formaldehyde),  and  others  containing  boric  acid,  as 
Dry  Antiseptic,  Preserving  Salts,  "A"  Preservaline,  Cream  Al- 
buminoid, Patent  "  M  "  Preservaline  and  Ozone  Antiseptic  Com- 
pound, are  employed  to  keep  milk  from  souring  without  the  use 
of  ice  or  cleanliness  by  killing  or  checking  the  growth  of  germs 
in  milk.  Their  use  is  contrary  to  law  and  detrimental  to  the  con- 
sumer's health,  especially  when  employed,  as  they  usually  are,  in 
a  careless  way,  without  regard  to  what  the  effect  of  a  considerable 
amount  of  the  chemical  might  be.  Thus  the  following  instance  is 
related  in  the  Year  Book  of  the  Department  of  Agriculture  for  1900 
of  a  case  where  a  preserving  fluid  wras  first  added  to  the  milk  by 
the  farmer,  then  by  the  collector  of  the  milk,  again  by  the  whole- 
sale dealer,  and  finally  the  fourth  dose  by  the  retail  dealer. 

If  it  were  impossible  to  produce  clean  milk  or  to  preserve  it  with 
ice,  and  if  preservatives  could  be  used  properly  in  a  harmless  dose, 
their  employment  might  be  permitted,  but  such  is  not  the  case. 

Significance  of  Germs  in  Milk 

The  growth  of  large  numbers  of  germs  in  milk  causes  it  to 
deteriorate  because  they  remove  nutriment  or  alter  the  milk  chemi- 
cally and  thus  lessen  its  food-value.  Ordinary  market  milk,  which 
is  overrun  with  germs,  loses  much  of  its  value  as  food  after 
it  is  twenty-four  hours  old.  The  ideal  result  would  be  reached 
if  milk  could  be  withdrawn  from  the  cow  absolutely  free  from  germs. 
This  might  be  possible  if  germs  did  not  enter  the  udder  in  the 


1 8  CLEAN  MILK 

;air  through  the  opening  in  the  teat  and  find  their  way  into  the  cavity 
or  milk-cistern  in  the  lower  part  of  the  udder.  Among  the  more 
common  germs  found  in  the  first  or  fore  milk  are  the  streptococci. 
Streptococci  are  those  germs  which  are  frequently  responsible  for 
various  forms  of  inflammation  in  man  and  animals,  and  are  also 
found  in  milk  withdrawn  from  inflamed  udders  of  cows  affected 
with  garget.  That  the  streptococci  ordinarily  present  in  the  teats 
of  healthy  cows  are  identical  in  appearance  with  the  disease-pro- 
ducing streptococci  is  now  known,  but  they  are  present  in  the 
cleanest  milk,  as  they  naturally  enter  the  teats  and  milk  cistern 
from  the  outer  air.  For  this  reason  the  fore  milk  is  rejected  by 
those  producing  clean  milk. 

Disease-producing  streptococci  are  perhaps  among  the  most  im- 
portant of  the  germs  causing  serious  forms  of  infantile  diarrhoeas. 
Therefore  when  streptococci  (with  leucocytes)  are  present  in  ex- 
cess the  milk  should  be  condemned  for  food  (see  p.  250).  As 
the  milking  proceeds  the  germs  in  the  milk-cistern  and  teat  are 
washed  away  so  that  the  latter  part  of  the  milk  withdrawn  is 
often  absolutely  free  from  germs  until  contaminated  with  the  out- 
side air.  Occasionally  germs  may  persist  in  milk  throughout  milk- 
ing, and  the  stripping^  may  contain  as  many  as  500  germs  to  the 
cubic  centimeter.  If  the  latter  part  of  the  milk  is  withdrawn 
through  an  absolutely  clean  milking  tube  into  an  absolutely  clean 
bottle,  it  will  often  be  wholly  without  germs,  and  may  keep  sweet 
for  months  or  years  if  it  does  not  come  in  contact  with  the 
air.  Such  painstaking  cleanliness  as  is  necessary  to  make  this  ex- 
periment successful,  is  not  of  course  practicable  in  actual  dairy 
work,  since  it  is  not  economically  possible  to  throw  away  a  larger 
part  of  the  milk  nor  to  withdraw  milk  so  that  it  will  not  come  in 
contact  with  air.*  Therefore,  under  any  ordinary  conditions  a  cer- 
tain number  of  germs  must  inevitably  be  present  in  the  cleanest 
milk — perhaps  200  to  4,000  as  the  least  number  to  the  cubic  centi- 
meter/j' 

*  Since  writing  the  above  the  use  of  the  milking  machine  (see  Appendix) 
makes  withdrawal  of  milk  without  exposure  to  air  practicable. 

f  The  average  contamination  of  milk  within  the  adder  amounts  to  500  bac- 
teria pet  C.c.  for  all  the  milk  from  out  milking;  while  there  are,  according  to 
Conn,  6,900  bacteria  on  the  average  in  the  foremilk. 


GERMS  IN  RELATION  TO  MILK  19 

Then,  if  the  milk  is  immediately  cooled  to  400  F.  and  retained 
at  this  temperature,  the  number  of  germs  will  lessen  until  it  is 
thirty-six  hours  old. 

The  presence  of  many  thousand  germs  to  the  cubic  centimeter 
in  milk  freshly  withdrawn  indicates  filthiness  of  the  cow,  milker 
or  surroundings.  This  is  especially  so  if  the  germs  are  of  the  putre- 
factive or  liquefying  type  (see  p.  23). 

The  existence  of  a  great  variety  of  germs  in  milk  several  hours 
old  signifies  contamination  of  the  milk  with  filth  also,  because  in 
clean  milk  only  one  kind  of  germs  (lactic  acid  bacilli)  are  found 
very  numerous  after  many  hours. 

While  the  mere  fact  that  milk  contains  a  vast  number  of  germs 
is  not  a  sure  proof  of  its  unwholesomeness — because  the  commonest 
germs  in  milk  are  harmless  and  because  milk  may  contain  but  a  few 
germs  and  these  may  be  the  cause  of  dangerous  disease  in  man — 
yet  the  estimation  of  the  number  of  germs  in  milk  is  to-day  the 
best  method  we  possess  for  determining  its  purity. 

Ordinary  market  milk  contains  as  many  germs  as  sewage,  and 
unusually  dirty  milk  contains  more  germs  than  sewage  was  ever 
known  to  hold.  This  is,  however,  not  at  all  a  fair  comparison,  for 
while  sewage  is  likely  to  contain  all  sorts  of  germs  of  disease,  the 
germs  in  dirty  milk  are  mostly  not  disease-germs. 

We  may  consider  the  influence  of  germs  in  milk  under  two 
heads:  1.  The  effect  of  germs  on  milk  and  its  products.  2.  The 
influence  of  germs  in  milk  on  the  consumer. 

I.  The  Effects  of  Germs  on  Milk  and  Its  Products. — All 
fermentation  and  putrefaction  or  rotting,  anywhere  and  of  anything, 
are  usually  due  to  germs.  The  changes  wrought  in  substances  by 
the  "  ferments  "  or  chemical  bodies — either  produced  by  germs  in 
milk  or  secreted  in  milk — and  by  the  ferments  in  the  digestive  juices 
of  animals,  must  also  be  included  under  the  head  of  fermentation. 

Germs   are  the  great  disintegrating  agencies   in  the  world; 


2o  CLEAN  MILK 

they  tend  to  break  up  complex,  natural  constituents  in  milk  and  its 
products  into  simpler  bodies.  The  commonest  germs  in  milk — as 
we  have  noted — are  those  causing  souring  of  milk;  they  are  in- 
variably present  and  are  about  the  only  kind  existing  in  very  clean 
milk.  They  act  to  ferment  or  change  the  natural  sugar  of  milk 
into  an  acid  (lactic  acid),  and  if  they  occur  in  large  numbers  a  few 
hours  after  milking  it  is  a  sign  that  the  milk  has  not  been  properly 
cooled  and  will  sour  early.  Lactic  acid  germs,  or  those  producing 
souring  of  milk,  besides  being  the  most  common,  are  of  most  im- 
portance in  their  influence  on  milk  and  its  products.  They  exist  in 
very  small  numbers  in  milk  soon  after  leaving  the  cow,  but  as 
they  grow  more  readily  than  all  other  germs  in  milk  at  favorable 
temperatures  (above  500  and  better  over  700  F.),  they  often  con- 
stitute almost  50%  of  all  the  germs  in  twenty-four  hours.  While, 
after  this  time,  they  gradually  crowd  out  the  different  varieties 
of  competing  germs  until  they  produce  so  much  acid  that  the 
milk  or  cream  sours  and  curdles,  and  they  have  multiplied  so  rapidly 
and  have  made  the  milk  so  unfavorable  for  other  germs  that  they 
form  from  90  to  99%  of  all  the  germs  present.  This  is  a 
most  favorable  occurrence,  because  the  flavor  of  most  butter  and 
cheese  is  chiefly  dependent  on  the  action  of  the  lactic  acid  germs,  and 
in  their  growth  they  protect  the  milk  from  the  action  of  miscellan- 
eous germs  which  would  spoil  these  products. 

Even  to  man  the  growth  of  the  lactic  acid  germs  is  a  favorable 
happening,  as  they  are  not  harmful  to  adults  in  themselves  and 
tend  to  check  the  development  of  other  harmful  germs  in  the  di- 
gestive canal.  Indeed  Metchnikoff,  perhaps  the  most  celebrated 
living  authority  on  the  action  of  germs  on  the  body,  believes  that 
lactic  acid  germs  in  sour  milk  constitute  one  of  the  best  agencies  for 
prolonging  life.  The  acidity  of  sour  milk  is,  however,  harmful  to 
children  and  may  cause  vomiting,  etc.  As  we  have  pointed  out, 
heating  milk  to  1550  or  1650  F.  readily  kills  the  lactic  acid  germs. 
Therefore  such  milk  does  not  sour,  but  is  changed  by  the  action  of. 


GERMS  IN  RELATION  TO  MILK  2r 

^>ther  harmful  germs  so  that  it  rots  or  putrefies  when  old.  A  low- 
temperature  (400  F.)  also  retards  the  development  of  the  lactic 
acid  germs  and  they  are  killed  when  the  milk  or  cream  becomes 
very  sour  (when  the  formation  of  lactic  acid  reaches  0.8-2.0  per 
cent),  by  means  of  the  lactic  acid  they  themselves  produce.  The 
action  of  these  lactic  acid  germs  is  taken  advantage  of  in  the  ripen- 
ing of  cream  for  butter  by  adding  them  in  great  numbers,  either  by 
the  use  of  sour  cream  or  milk,  or  by  laboratory  methods  by  which 
they  can  be  obtained  in  pure  culture — that  is,  free  from  admixture 
with  other  varieties  of  germs  (see  page  59).  Lactic  acid  germs  are 
not  found  in  milk  when  it  leaves  the  udder,  but  enter  the  milk  when 
it  is  exposed  to  air.  They  are  thought  to  reside  on  the  skin  of  the 
cow,  in  dust,  in  the  air  or  surroundings  of  the  barn.  But  milk 
utensils — unless  sterilized  by  steam  or  boiling  water — are  the  chief 
means  of  supplying  milk  with  lactic  acid  germs.  This  happens 
because  sour  milk  germs  lurk  in  the  corners  and  rough  surfaces  and 
crevices  of  milk  vessels.  So,  from  the  milk  pail  to  the  shipping  can 
or  milk  bottle,  each  and  every  utensil  adds  its  quota  of  lactic  acid 
.germs — unless  the  utensils  have  been  thoroughly  washed  and  heated 
for  some  time  to  the  boiling  point.  Ordinary  market  milk  at  500  F. 
sours  in  120  hours;  at  6o°  F.  it  sours  in  66  hours;  at  980  it  sours 
in  16  to  18  hours. 

There  are  two  types  of  lactic  acid  germs :  ( 1 )  The  more  com- 
mon (B.  lactis  acidi  or  Streptococcus  lacticus*)  constitutes  on  the 
average  about  90%  of  all  the  germs  in  milk.  It  grows  best  without 
air  (anaerobic),  and  so  milk  sours  best  in  deep  vessels.  (2)  The 
Jess  common  type  of  lactic  acid  germ  is  that  which  causes  gassy 
milk  and  cheese  (B.  lactis  aerogenes)  and  is  derived  also  from  the 
dirt  of  the  cow  and  does  not  come  from  the  udder.  Certain  germs 
capable  of  producing  disease  in  man  also  sour  milk. 

Of  these  the  colon  bacillus  is  derived  from  manure  of  the  cow. 
And  the  germs  causing  inflammation  of  the  udder  (streptococci)  in 

*  Streptococcus  lacticus  rightly  forms  a  third  group  of  lactic  acid  bacteria.  It 
is  the  commonest  organism  souring  milk,  it  differs  from  lactic  acid  bacteria  (which 
are  oval,  in  pairs  or  short  chains)  in  appearance  and  is  indistinguishable  from 
disease-producing  streptococci  (S.  pyogenes)  but  is  harmless  to  man  occurring  in 
uncontaminated  milk  from  healthy  cows. 


22  CLEAN  MILK 

the  cow  may  act  as  lactic  acid  germs  and,  on  entering  milk,  may- 
cause  disease  in  man  drinking  it. 

Altogether  some  ioo  varieties  of  germs  may  lead  to  lactic  acid 
fermentation  and  souring  of  milk.  In  general  it  may  be  said  that 
when  80  to  90%  of  the  germs  in  milk  belong  to  the  more  com- 
mon type  of  lactic  acid  germs  the  milk  is  wholesome — even  if  germs 
are  in  great  numbers.  If  there  are  less  than  20%  of  lactic  acid 
germs  in  such  milk  it  should  be  regarded  as  unfit  food  (Conn). 
Sour  milk  becomes  covered  in  time  by  moulds  (Oidium  lactis)  and 
colored  spots  produced  by  various  bacteria  and  fungi. 

At  the  Paris  exposition  of  1900  there  was  an  exhibit  of  dairy 
products,  under  care  of  Major  Alford,  of  the  U.  S.  Department  of 
Agriculture,  which  consisted  of  fresh  milk  and  cream  shipped  from 
Illinois,  New  Jersey  and  New  York  in  hot  weather  (July).  Com- 
ing some  3,000  to  4,000  miles,  the  cream  and  milk  were  perfectly 
sweet  a  fortnight  after  being  bottled,  while  the  only  other  com- 
petitor was  the  French  with  a  local  supply  which  did  not  keep  a 
day  after  reaching  the  grounds.  In  the  Chicago  National  Dairy 
Show  in  1906  a  sample  of  cream  shipped  over  1,000  miles  was  stilt 
sweet  at  the  end  of  7  weeks.  Cleanliness  and  cold  were  the  only 
methods  used  in  so  wonderfully  preserving  this  milk. 

If  milk  is  very  dirty,  however,  it  is  not  safe  to  keep  it  too  long- 
with  ice,  even  if  it  does  not  sour  and  is  unaltered  in  taste,  as. 
various  sorts  of  harmful  germs  may  develop  at  a  low  temperature. 
Thus,  milk  containing,  soon  after  milking,  some  800,000  germs  to 
the  cubic  centimeter,  after  four  days  at  41  °  F.  contained  almost  five 
million  germs  and  became  sour.  At  the  end  of  ten  days  this  same 
milk  contained  over  400  million  germs,  or  over  ten  times  the  num- 
ber of  germs  in  the  same  milk  kept  the  same  time  at  590  F.*  The 
milk  kept  at  a  higher  temperature  soured  more  quickly  and  the 
acid  destroyed  many  of  the  germs  in  the  process. 


Swithinbank  &  Newman. 


GERMS  IN  RELATION  TO  MILK  23 

The  kind  of  germs  which  will  grow  in  milk  depends  on  the 
temperature  of  the  milk.  Below  6o°  F.  miscellaneous  germs  grow, 
but  those  which  sour  milk  do  not  flourish.  Therefore  in  dirty 
milk  which  kept  for  some  days  below  50 °  F.  the  miscellaneous 
germs  may  be  abundant.  These,  or  the  poisons  they  produce,  may 
cause  disease  in  the  human  being — chiefly  nausea  and  vomiting,  and 
cholera  infantum.  The  harmless  lactic  acid  germs  flourish  at  room 
temperature  (6o° — 70  °  F. ).  Comprising  less  than  1%  often  in 
new  milk,  in  24  hours  at  room  temperature  they  may  reach  50%, 
and  in  48  hours  95%  of  all  the  germs  in  the  milk.  At  this  time 
the  milk  sours,  the  acid  having  killed  all  the  other  germs. 

At  temperatures  between  8o°  and  ioo°  F.  various  different 
kinds  of  germs  may  predominate,  but  often  the  germs  which  lead 
to  formation  of  gas  in  milk  and  cheese  are  in  most  abundance  (B. 
lactis  aerOgenes). 

It  will  thus  be  noted  that  sweet  milk  may  be  much  more  harm- 
ful to  health  than  sour  milk,  i.  e.,  if  it  was  contaminated  and  has 
been  kept  sweet  by  means  of  a  low  temperature. 

There  is  a  large  class  of  germs  known  as  putrefactive  germs 
because  they  produce  changes  in  milk  which  are  akin  to  rotting  of 
meat.  If  these  continue  to  develop  long  enough  they  may  impart 
a  bad  odor  to  milk  or  its  products  and  are  likely  to  induce  diarrhceal 
diseases  in  children. 

Among  the  more  common  putrefactive  bacteria  which  work 
harm  to  milk  are  the  "  liquefiers."  They  enter  milk  in  manure  and 
filth  and  thus  to  a  considerable  degree  indicate  contamination  of 
milk  with  filth. 

The  liquefiers  may  at  first  cause  "  sweet  curdling "  in  milk 
from  the  action  of  a  rennet-like  ferment  they  produce.  Later — or 
sometimes  immediately — the  liquefiers  alter  and  dissolve  the  casein 
of  milk  by  means  of  another  ferment  (casease)  which  digests  the 
casein.  The  milk  then  becomes  clear  as  water  or  variously  colored 
and  has  a  putrid  odor. 


24  CLEAN  MILK 

The  liquefiers  also  liquefy  the  substance  on  which  germs  are 
commonly  grown  in  the  laboratory,  i.  c,  gelatine ;  hence  their  name. 

The  putrefactive  germs  or  liquefiers  may  amount  to  20  or  50% 
of  the  germs  present  in  milk  at  the  end  of  24  hours  (Conn), 
but  from  this  time  on  they  are  commonly  crowded  out  by  growth 
of  the  lactic  acid  bacteria  and  gradually  disappear. 

There  are  a  great  number  of  germs  in  milk  which  apparently 
have  no  effect  upon  its  character  and  also  are  not  harmful  to  the 
consumer.  It  is  practically  impossible  to  discover  the  germs  of 
special  diseases  in  milk  with  any  certainty,  so  that  besides  recogniz- 
ing the  chief  types  of  germs — the  lactic  acid  germs,  the  putrefactive 
germs,  and  miscellaneous  germs  whose  action  is  unknown  to  us — 
the  best  that  can  be  done  at  present  is  to  estimate  the  number  of 
germs  in  milk  per  cubic  centimeter.  Large  numbers  of  miscellan- 
eous and  putrefactive  germs  signify  that  the  milk  is  contaminated 
with  filth  and  is  most  dangerous.  Large  numbers  of  lactic  acid 
germs  indicate  that  the  milk  has  not  been  kept  cool  enough  or  is 
old.  Freedom  from  any  considerable  number  of  germs  is  a  pretty 
certain  sign  that  the  milk  has  been  drawn  from  the  cow  and  handled 
in  a  cleanly  manner;  has  been  properly  cooled  and  is  likely  to  be 
uncontaminated  with  disease-germs.  This  is  the  justification  of 
cities  which  require  that  milk  shall  not  contain  more  than  a  specified 
number  of  germs  (bacteria)  to  the  cubic  centimeter. 

Thus  the  law  in  force  in  Boston  requires  that  milk  sold  in  that 
city  shall  not  contain  more  than  500,000  germs  to  the  cubic 
centimeter. 

It  has  generally  been  admitted  that  it  is  difficult  to  obtain  any 
large  supply  of  milk  which  shall  certainly  contain  less  than  10.000 
germs  to  the  cubic  centimeter.  In  various  parts  of  the  United  States 
milk  of  such  purity  is  now  sold  and  is  often  called  "  Certified  Milk." 
The  name  "  Certified  Milk  "  originated  with  Henry  L.  Coit,  M.D. 
He  established  a  commission  of  medical  men  in  Newark.  N.  J.,  in 
1893,  wno  made  an  agreement  with  a  dairyman  of  Caldwell,  N.  J., 


tf  r  Stat*  Collet* 


GERMS  IN  RELATION  TO  MILK  25 

to  furnish  milk  subject  to  their  requirements  and  inspection  which 
should  be  known  as  "  Certified  Milk  "  when  approved  by  the  com- 
mission. 

Certified  milk  is  that  produced  under  a  legal  contract  between 
2.  medical  milk  commission  and  a  dairyman  to  conform  to  certain 
recognized  requirements.  The  name  was  registered  in  U.  S.  Patent 
Office  in  1904  with  the  understanding  that  it  should  be  used  by 
medical  milk  commissions  but  not  by  dairymen  not  supplying  milk 
to  medical  milk  commissions. 

New  York  State  has  passed  a  law  preventing  the  use  of  the 
word  certified  milk  except  by  permission  of  medical  commissions 
formed  by  county  medical  societies  which  are  organized  and  char- 
tered by  the  State  Medical  Society.  Similar  laws  should  be  passed 
in  other  states  and  offenders  should  be  prosecuted. 

Examinations  of  certified  milk  should  be  made  by  chemist, 
bacteriologist  and  veterinarian  (stock  and  stabling,  etc.)  twice 
monthly  and  members  of  commission  once  monthly.* 

Any  person  who  pretends  to  produce  clean  milk  must  submit 
to  the  germ  standard,  as  this  is  the  best  means  of  estimating  purity 
which  we  now  possess.  Exactly  what  that  standard  should  be  has, 
however,  pot  been  generally  agreed  upon.  It  is  not  unusual  to  find 
10,000  germs  as  the  maximum  number  per  cubic  centimeter  per- 
mitted in  certain  localities  for  certified  milk.  The  standard  of 
Albany  for  certified  milk  has  been  80,000 ;  for  Rochester  and  New 
York  City,  30,000;  for  Philadelphia  and  Milwaukee,  10.000.  The 
U.  S.  Agricultural  Department  standard  is  10,000,  and  this  should 
now  be  considered  the  maximum,  as  it  was  originally  established 
by  Coit.  It  is  perfectly  possible  to  produce  milk  which  shall  not 
contain  more  than  a  few  hundred,  or,  at  most,  not  more  than  2,000 
to  4,000  germs  to  the  cubic  centimeter  without  great  expense,  if 
every  precaution  to  secure  cleanliness  be  observed  in  milking  and 
handling  the  milk.     At  Newbursrh.  N.  Y.,  certified  milk  has  been 


*  For  blank  forms  to  be  used  in  these  examinations,  see  p.  204. 


26  CLEAN  MILK 

produced  from  a  herd  of  ioo  grade  Jersey  and  Guernseys  which 
has  had  a  bacterial  count  below  1,000  for  one  year  and  an  average 
of  150  bacteria  for  15  successive  weeks  from  samples  taken  at  ran- 
dom in  the  city. 

The  usual  contamination  of  milk  with  germs  may  be  judged 
by  the  following  figures  with  the  understanding  that  great  improve- 
ment is  taking  place  owing  to  the  interest  which  has  been  shown 
in  the  matter  of  obtaining  a  pure  milk  supply  in  recent  years  by 
physicians  and  others.  In  Boston,  during  the  spring  of  1890,  57 
samples  of  milk  showed  an  average  of  2,355,500  germs  in  the 
better  class  milk,  and  of  4,557,000  germs  in  grocery  milk.  In  winter 
the  growth  of  germs  is  considerably  lessened  by  the  colder  temper- 
ature and  this  is  somewhat  counterbalanced  by  the  filthier  condi- 
tions of  the  barn  floors,  air  and  of  the  animals.  On  the  whole, 
winter  milk  is,  however,  much  freer  from  germs.  The  New  York 
County  Medical  Society  issue  a  certificate  of  inspection  to  farmers 
who  will  follow  their  directions  for  producing  a  second-grade,  pure 
milk  which  shall  not  average  over  100,000  germs  from  May  to 
October,  and  not  over  60,000  germs  from  October  to  May.  In 
Seattle  I  found  in  twenty-eight  examinations  of  different  samples 
of  milk  on  as  many  days  in  May  and  June,  that  sixteen  samples 
averaged  over  3,000,000  germs,  and  twelve  samples  less  than  1,000,- 
000  germs  per  cubic  centimeter.  The  examination  of  these  milk 
samples  was  done  when  the  milk  was  fifteen  to  thirty-six  hours  old, 
on  the  way  to  the  consumer's  house,  being  taken  from  the  delivery 
wagons  or  on  arrival  of  the  milk  train. 

A  great  many  conditions  may  alter  the  number  of  germs  in 
milk  if  milk  is  not  produced  and  handled  in  a  proper  manner.  Time 
and  temperature  are  the  two  most  important  factors  upon  which 
the  growth  of  germs  depends — and  the  greatest  of  these  is  temper- 
ature. The  milk  from  one  farm  examined  at  the  same  hour  on 
two  consecutive  days  averaged  1,150.000  germs  on  the  first  day — 
which  was  warm  for  May — and  48,000  germs  the  following  day, 


GERMS  IN  RELATION  TO  MILK 


27 


which  was  cold  and  rainy.  The  great  increase  of  germs  when  milk 
is  kept  at  improper  temperatures,  we  have  already  noticed,  the 
number  of  germs  in  such  milk  depending  entirely  upon  its  age.  To 
show  the  effect  of  dust  and  unclean  utensils  on  milk  I  may  cite  the 
following:  A  sample  of  pasteurized  milk,  taken  from  a  delivery 
wagon  and  examined  by  the  writer,  contained  seven  million  germs, 
while  from  the  same  wagon  was  also  taken  a  sample  of  the  same 
milk  put  into  sealed  milk  bottles  which  contained  but  24,000  germs 
to  the  cubic  centimeter.  The  first  sample  was  taken  from  a  large 
can  which  was  frequently  opened  to  pour  out  small  quantities  for 
consumers  and  very  likely  the  can  was  unclean  before  the  milk  was 
put  into  it. 

After  the  milk  is  withdrawn  from  the  cow  the  number  of 
germs  in  it  generally  diminishes  for  a  longer  or  shorter  time, 
and  after  this  period  the  number  rapidly  increases.  Thus  at  forty 
degrees  the  number  of  germs  may  not  be  greater  in  thirty  or  forty 
hours  than  it  was  when  the  milk  was  first  withdrawn.  At  a  higher 
temperature  the  germs  begin  to  multiply  in  the  milk  as  soon  as  the 
third  hour  after  it  has  left  the  cow.  Each  variety  of  germ  has  a 
special  temperature  at  which  it  flourishes  to  best  advantage.  The 
lactic  acid  germs  grow  more  favorably  at  comparatively  high  tem- 
peratures— from  70  °  to  900  F.,  or  even  higher. 

There  are  certain  special  germs — not  all  of  which  have  been 
studied — which  produce  special  faults,  or,  as  they  have  been  called, 
diseases  of  milk. 

Thus  the  butyric  acid  germs  develop  that  acid  by  the  splitting 
up  the  fat  in  rancid  butter.  Yellow,  red,  blue,  brown  and  green 
milk  are  rarely  seen  and  the  particular  coloration  is  due  to  changes 
produced  in  the  milk  by  special  germs.  A  turnip  taste  is  often 
given  milk  by  a  particular  germ  (B.  fcetidus  lactis).  So  also  are 
slimy  milk,  bitter,  stringy  and  soapy  milk,  owing  to  special  germ- 
development  and  its  effect  on  milk.  It  is  thought  that  slimy  milk 
may  be  caused  by  cows  eating  the  leaves  of  the  plant,  Pinguicula 
vulgaris,  since  placing  the  leaves  in  milk  will  induce  this  condition. 


-28  CLEAN  MILK 

Bitter  milk  may,  however,  be  produced  by  other  causes  than  the 
growth  of  germs,  as  by  certain  foods  which  the  cow  may  eat 
(lupines,  ragweed,  wormwood,  cabbages,  raw  Swedish  turnips),  or 
as  seen  in  milk  during  late  lactation  or  in  garget.  In  these  cases  the 
milk  is  bitter  soon  after  it  leaves  the  cow,  but  bitterness  induced  by 
the  growth  of  germs  is  usually  not  seen  except  in  old  milk. 

Red  milk  may  be  due  to  contamination  with  blood,  following 
injury  to  the  udder  or  teats.  Red  milk  is  said  to  occur  owing  to 
cows  eating  large  amounts  of  sedges,  rushes,  madder  root,  alkanet, 
field  horsetail,  meadow  saffron,  and  knot  grass. 

Aside  from  slimy  milk  caused  by  pus  escaping  from  inflamed 
udders,  a  special  germ  (B.  lactis  viscosus)  is  commonly  the  source 
of  this  condition.  This  germ  exists  chiefly  in  water  and  in  dust.  To 
prevent  slimy  milk  one  must  avoid  contamination  of  the  milk  with 
unboiled  water  or  with  dust.  Thus  all  milk  utensils  (including 
strainer  cloths)  must  be  thoroughly  sterilized  by  boiling  or  by- 
steam  in  a  sterilizer. 

Tanks  containing  water  for  cooling  cans  must  be  sterilized  by 
using  a  solution  of  bichromate  of  potash  ( i  ounce  to  the  cubic  foot 
of  water).  Cans  filled  with  milk  may  be  kept  in  this  solution,  pro- 
viding it  is  not  spilled  into  the  milk.  Not  a  drop  of  unboiled  water 
should  be  permitted  to  drop  into  milk  or  milk  utensils.  Floors  of 
rooms  in  which  milk  is  kept  may  be  disinfected  by  5%  sulphuric 
acid  solution.  Milk  utensils  must  be  kept  inverted  and  covered  when 
not  in  use. 

Cows  should  not  be  allowed  to  soil  their  udders  by  wading  in 
mud  and  water.     Slimy  milk  is  not  harmful  but  very  distasteful. 

This  whole  book  is  chiefly  devoted  to  the  influence  of  germs 
on  milk,  in  one  way  or  another,  and  further  reference  to  the  sub- 
ject will  be  found  under  the  special  topics  considered. 

2.  Action  of  Germs  in  Milk  Upon  the  Consumer. — As  we 
have  already  intimated,  germs  do  not  enter  milk  during  its  forma- 


GERMS  IN  RELATION  TO  MILK  2$> 

lion  in  the  udder  of  the  cow,  in  normal  conditions,  but  only  gain 
entrance  to  milk  through  the  medium  of  the  air  when  the  milk 
flows  into  the  receptacle  or  cistern  which  communicates  with  the- 
air  through  the  opening  in  the  teat.  We  showed  that  if  the 
milk  cistern  was  washed  out  clean  and  that  if  then  a  milking  tube 
was  introduced  into  the  teat  it  was  possible  to  secure  milk  free  from 
germs  altogether  and  which  would  therefore  remain  sweet  indefin- 
itely if  kept  in  a  sealed  flask.  If  the  cow  is  suffering  from  a  germ 
disease  it  is  possible  for  the  germs  to  get  into  the  milk,  during  its 
formation  in  the  udder,  from  the  blood  of  the  animal,  if  it  has 
a  general  disease ;  or,  what  is  still  more  likely,  if  there  is  disease 
of  the  udder  itself,  the  germs  may  find  their  way  into  the  milk 
directly  from  the  diseased  parts.  While,  in  the  case  of  most  gen- 
eral infectious  or  germ  diseases  of  cows,  the  germs  will  not  escape 
in  the  milk  yet  the  toxins  or  poisons  produced  by  these  germs  may 
so  escape.  Inflammation  of  the  udder  may  be  caused  by  various 
germs,  of  which  the  germ  of  tuberculosis  is  one  and  perhaps  the 
most  dangerous.  This  germ  is  found  in  milk,  then,  more  frequently 
when  tuberculosis  affects  the  udder  (tuberculosis  of  the  udder 
occurs  in  2-8%  of  all  cases  of  tuberculosis),  but  also  when 
tuberculosis  attacks  other  parts  of  the  cow. 

Thus  Mohler  fed  and  also  inoculated  (injected  under  the 
skin)  guinea  pigs  with  milk  from  56  tuberculous  cows,  which 
were  free  from  udder  tuberculosis,  and  found  that  the  milk  from 
21%  of  these  cows  contained  the  virulent  germs  of  tuberculosis. 

Moreover,  the  milk  becomes  infected  in  other  ways:  1.  Tub- 
erculosis of  the  bowels  and  womb  of  cows  is  common  and  the  dis- 
charges from  these  parts  soil  the  cow  and  thus  the  milk.  2.  The 
germs  of  tuberculosis  from  consumptive  persons  (tuberculosis  of 
the  lungs)  may  enter  milk  as  dried  expectoration  blowing  about  in 
dust  (rare)  ;  or  by  means  of  the  hands  of  consumptive  milkers  be- 
ing soiled  with  their  expectoration  (rare).  3.  Again,  the  dis- 
charges  from  tuberculous  cows    (expectoration,   manure,    vaginal 


3o  CLEAN  MILK 

discharge)  contaminate  the  surroundings,  dust,  utensils,  water, 
fodder,  etc.,  and  so  may  find  their  way  into  milk,  as  they  do 
into  well  animals.  While  it  has  generally  been  thought  that  the 
tuberculosis  germs  in  milk  are  commonly  derived  from  the  udder 
of  the  diseased  cow  it  now  seems  probable  that  the  contamination  of 
milk  with  manure  of  tuberculous  cows  is  the  most  frequent  source 
of  the  germ,  Mohler  has  found  the  germs  of  tuberculosis  in  the 
manure  of  over  41  per  cent,  of  cows  of  healthy  appearance  which 
showed  no  evidence  of  tuberculosis  save  by  the  tuberculin  test. 
The  tuberculosis  germs  present  in  the  manure  are,  however,  chiefly 
derived,  not  from  disease  of  the  bowel,  but  from  the  blood  or  dis- 
charge coughed  up  from  the  lungs  and  then  swallowed  by  the  animal. 

The  results  of  the  examinations  of  some  1.287  samples  of 
milk,  chiefly  by  intraperitoneal  injection  into  guinea  pigs  and  rab- 
bits, by  some  18  or  20  experimenters  in  different  European  cities, 
show  that  9%  of  milk  contains  active  germs  of  tuberculosis. 
Anderson  has  shown  that  in  Washington,  D.  C,  approximately 
11%  of  the  dairies  supply  milk  containing  virulent  tubercle  bacilli. 

The  percentage  of  cows  affected  with  tuberculosis  varies  widely 
in  different  herds  and  localities.  Thus  large  herds  are  more  apt 
to  be  tuberculous  and  80  to  90%  of  the  animals  may  have  tuber- 
culosis. In  smaller  herds  and  in  those  living  chiefly  outdoors 
the  percentage  may  vary  from  zero  to  5070  affected  with  the 
disease.  Of  24,685  cows  tuberculin-tested  in  Massachusetts,  50% 
were  found  to  be  tuberculous.  The  latest  statistics  (1908)  concern- 
ing the  prevalence  of  tuberculosis  among  cattle  in  the  United  States 
are  those  of  Melvin  based  on  approximately  54  million  cattle 
slaughtered  and  inspected  for  food,  and  400,000  (mostly  dairy 
cattle)  tested  with  tuberculin. 

He  estimated  that  ten  per  cent,  of  milch  cows  and  one  per  cent. 
of  other  cattle  have  tuberculosis.  The  use  of  tuberculin  is  the  only 
positive  test. 

Just  how  common,  and  how  important,  therefore,  is  tubercu- 


GERMS  IN  RELATION  TO  MILK  31 

losis  in  the  cow  a  source  of  the  disease  in  man  through  drinking 
milk  of  tuberculous  cows,  it  is  impossible  to  say,  but  from  recent 
studies  it  is  probable  that  from  10  to  23  per  cent,  of  tuberculosis 
in  children  owes  its  origin  to  milk,  and  in  consequence  it  is  essen- 
tial that  all  cows  should  be  tested  with  tuberculin,  to  exclude  the 
possibility  of  tuberculosis,  before  the  milk  is  used  for  any  purpose. 
*  Koch  states  that  of  all  the  human  deaths  from  tuberculosis, 
eleven  twelfths  are  owing  to  consumption  (tuberculosis  of  the 
lungs)  and  in  this  form  of  the  disease  the  bovine  type  of  germ 
has  not  been  found.  Therefore  he  does  not  attribute  consumption 
to  drinking  milk. 

Theobald  Smith  attributes  half  of  the  cases  of  tuberculosis  of 
the  abdomen  and  of  the  glands  of  the  neck  in  children  to  the  bovine 
type  of  bacilli  and  therefore  to  milk. 

Nathan  Raw  ascribes  tuberculosis  of  the  lungs,  larynx  and  in- 
testines in  man  to  the  human  type  of  bacillus;  while  human  tuber- 
culosis of  the  peritoneum,  glands,  joints,  brain  and  skin,  together 
with  the  acute  miliary  form,  he  believes  are  due  to  the  bovine 
bacillus  conveyed  to  man  only  in  milk. 

The  germs  of  tuberculosis  are  not  found  only  in  milk,  but  in 
cream,  cheese  and  butter. 

Garget  or  inflammation  of  the  udder  (mastitis)  is  caused  by 
external  injuries  and  by  infection  with  various  germs  which  cause 
inflammation  elsewhere  in  the  body  (as  streptococci,  staphylococci, 
colon  bacilli  and  diplococci).  These  germs  escape  in  the  milk  and 
so  give  rise  to  disease  in  persons  consuming  it.  The  milk  is  al- 
tered in  character  and  is  apt  to  be  lessened  in  amount.  It  contains 
small  whitish  or  yellowish  lumps  (pus  and  fibrin)  and  is  often 
bloody,  slimy  or  stringy.  Such  milk  may  have  a  bad  odor  and  taste 
and  may  quickly  curdle. 

The  commonest  disorders  produced  in  man  by  drinking  milk 


*  Internat.  Congress  of  Tuberculosis,  1908. 


2,2  CLEAN  MILK 

from  cows  with  garget  are  digestive — as  vomiting  and  diarrhea 
with  prostration.  Also  severe  sore  throat  (resembling  follicular 
tonsillitis  or  diphtheria)  and  a  condition  simulating  scarlet  fever 
are  seen.  Garget  is  more  common  before  or  after  calving  and  is 
discovered  through  the  altered  character  of  the  milk  and  the  appear- 
ance of  flakes  or  small  lumps  in  the  milk,  pr  stringy,  bloody  or  thick 
milk,  upon  the  cheese-cloth  strainer  covering  the  milk  pail ;  by 
the  occurrence  of  tenderness  and  lumpiness  and  swelling  of  the 
udder,  and  by  the  presence  of  the  germs  (noted  above)  in  the 
milk  (see  p.  31).  Milk  from  cows  with  garget — even  when  only 
one  quarter  of  the  udder  is  lumpy — is  unfit  for  human  consumption. 
By  boiling  such  milk  for  10  minutes  it  may  be  safely  fed  to  animals. 
In  the  case  of  tuberculosis  of  the  udder  there  is  also  hardening 
and  enlargement  of  the  udder — either  affecting  the  whole  udder 
or  not  uncommonly  one  of  the  rear  quarters  of  the  udder.  En- 
largement of  the  glands  above  and  behind  the  udder  (retromam- 
mary) is  frequently  the  first  sign.  The  milk  secretion  lessens, 
the  color  and  consistency  changes  to  a  yellowish  or  reddish,  thin 
fluid,  with  flakes  of  larger  size  than  usual,  and  on  standing  there 
is  a  deposit  of  thick  substance  with  watery  fluid  above.  Fin- 
ally, in  advanced  cases,  the  secretion  is  thick  and  yellowish  from 
pus  and  contains  curds,  has  an  alkaline  reaction,  and  is  wanting 
in  milk  sugar.  Tuberculous  disease  of  the  udder  generally  follows 
tuberculosis  in  other  parts  of  the  body  (for  method  of  finding  the 
germs  of  tuberculosis  in  milk,  see  pp.  37,  276). 

The  most  marked  chemical  changes  in  milk  from  cows  with 
mastitis  or  udder  tuberculosis  consist  in  diminished  content  of  milk 
sugar  and  increase  in  albumin  and  globulin  from  the  contamination 
of  milk  with  serum,  blood  and  pus. 

The  milk  from  such  cows  may  communicate  the  inflammation 
of  the  udder  to  other  cows  in  the  same  barn  by  means  of  germs 
carried  by  the  milker's  hands.  Therefore  cows  with  caked  or  in- 
flamed udders  should  be  kept  apart  and  milked  by  one  not  milking 


GERMS  IN  RELATION  TO  MILK  33 

the  healthy  cows.  Nodules  (or  the  miliary  form)  of  actinomycosis 
may  occur  in  the  udder  and  the  ray  fungi  from  the  disease  may 
escape  into  the  milk  and  produce  the  disease  in  man,  when  it  is 
used  as  food  by  him.  Botryomycosig  may  also  attack  the  udder  and 
render  the  milk  unfit  for  food.  The  milk,  butter,  buttermilk  and 
cheese  from  cows  with  foot-and-mouth  disease  lias  been  the  means 
of  communicating  this  disease  to  man,  giving  rise  in  him  to  sore 
mouth,  tender  swellings  under  the  jaw,  an  eruption  of  blisters  or 
"cold  sores"  on  the  face,  fever  and  disturbance  of  the  digestion. 
Boiling  and  pasteurization  (1800  F.)  destroys  the  germs  of  foot- 
and-mouth  disease.  Cow  pox,  milk  fever,  anthrax  and  pleuro- 
pneumonia (?)  in  cows  have  been  conveyed  by  the  germs  of  these 
diseases,  in  their  milk,  to  human  beings. 

Some  special  diseases  of  cows  have  been  studied  in  relation 
to  infection  of  milk.  Thus  in  that  fatal  form  of  dysentery  of  new- 
born calves  (due  to  colon  bacilli  and  proteus  forms),  and  in  in- 
fected navels  of  the  new-born  (septic  umbilical  phlebitis  due  to  strep- 
tococci, staphylococci,  colon  bacilli,  etc.),  which  is  also  accompanied 
with  diarrhea,  the  milk  is  apt  to  be  contaminated  with  the  germs  of 
these  diseases  in  the  atmosphere.  Cows  with  an  often  fatal  form  of 
bloody  diarrhea,  accompanied  by  fever  (hemorrhagic  enteritis  due 
to  some  of  the  colon  group),  may  secrete  milk  containing  the  germs. 
of  the  disorder  and  these  may  produce  typhoid-like  conditions  in. 
man  consuming  the  milk.  In  various  digestive  disturbances  of  cows 
the  milk  is  apt  to  be  altered  in  taste  (salty  or  bitter)  and  appearance 
(thin,  yellowish,  or  it  undergoes  "sweet  curdling"). 

Cows  having  a  foul  discharge  from  retained  afterbirth  and  in- 
flammation of  the  womb  (septic  metritis)  should  be  removed  from 
the  barn,  as  the  odor  and  germs  in  the  vaginal  discharge  (colon 
bacilli  and  cocci  of  various  kinds)  will  contaminate  the  milk  of 
neighboring  healthy  cows.  The  milk  from  such  diseased  cows  is 
not  fit  for  use. 

Cows  having  open  sores,  especially  on  the  udder  and  teats,  are 


34 


CLEAN  MILK 


apt  to  contaminate  their  milk  with  the  special  germs  to  be  found 
in  suppurating  wounds.  Cows  suffering  from  fevers  of  any  de- 
scription yield  milk  which  may  either  contain  special  germs  caus- 
ing these  disorders,  or  the  poisons  produced  by  these  germs. 

Cows  with  lockjaw  (tetanus)  or  rabies  may  communicate 
these  diseases  to  man  by  means  of  the  specific  germs  in  their  milk. 
There  appears  to  be  some  doubt  as  to  whether  these  disorders  have 
ever  been  actually  transmitted  to  persons  through  the  milk  of  cows 
sick  of  tetanus  or  rabies,  but  such  milk  should  never  be  consumed  by 
man  or  animals. 

Milk  sickness  in  man  is  due  to  a  special  bacillus  (B.  lactimorbi) 
escaping  in  the  milk  of  cows  suffering    from  Trembles,    (p.    78). 

The  following  drugs  are  known  to  escape  in  some  amount  in 
milk  when  given  to  cows.  Other  medicines  may  be  excreted  in  milk 
also,  as  the  subject  has  not  been  thoroughly  studied.  On  general 
principles  no  powerful  drug  should  be  given  to  cows  supplying 
market  milk.  Harmless  drugs,  as  iron  or  simple  bitters,  would  not 
damage  the  milk. 


Opium 

Mercury 

Creolin 

All   volatile   oils 

Lead 

Colchicum 

Purgative  ! 

salts 

Zinc 

Euphorbium 

Rhubarb 

Iron 

Ergot 

Senna 

Bismuth 

Salicylic  acid 

Castor  oil 

Neutral  salts 

Veratrine 

Scammony 

Ammonia 

Strychnine 

Jalap 

Acids 

Croton  oil 

Iodine 

Sulphur 

Aloes 

Potassium 

iodide 

Atropin 

Turpentine 

Antimony 

Copper 

Arsenic 

Carbolic  acid 

It  may  be  positively  affirmed  that  the  milk  from  a  sick  cow  or 
one  receiving  powerful  drugs,  is  not  fit  for  human  consumption. 
The  milk  of  tuberculous  cows  may  be  safely  fed  to  swine  or  calves 
after  boiling  for  ten  or  more  minutes. 


GERMS  IN  RELATION  TO  MILK  35 

The  germs  of  typhoid  fever,  diphtheria  and  scarlet  fever  * 
(rarely  of  cholera,  dysentery,  malta  fever,  from  goat's  milk,  and 
smallpox)  occasionally  find  their  way  into  milk,  owing  to  the  milk 
coming  in  contact  with  human  patients  suffering  from  these  diseases, 
or  with  their  surroundings,  or  from  contamination  of  milk  or  milk 
utensils  with  water  harboring  the  germs  of  typhoid  fever. -j-  Also, 
"by  wading  in  filth  containing  the  bowel  and  urinary  discharges  of 
human  beings,  cows  may  contaminate  their  udders  with  germs  of 
typhoid  fever  and  thus  convey  them  to  milk. 

Other  agencies  by  which  disease  germs  may  be  carried  to 
milk  and  by  which  many  cases  of  typhoid  fever,  diphtheria  and  scar- 
let fever  have  been  communicated  to  man  are  as  follows :  by  attend- 
ants in  the  sick  room  coming  in  contact  with  milk,  by  dish  cloths, 
brushes  and  other  articles  coming  in  contact  with  the  sick  and  milk 
utensils  as  well,  by  contact  of  milk  with  flies,  dust,  and  by  contact 
of  milk  with  persons  handling  human  excrement. 

The  chief  source  of  milk  infection  is  from  patients  at  the 
farm,  dairy  or  shop.  Persons  in  the  first  stages  of  disease,  or 
again  those  who  carry  the  germs  about  with  them  after  they  recover, 
are  especially  likely  to  infect  milk.  Thus  so-called  "  typhoid  car- 
riers "  may  disseminate  germs  for  years  from  the  bowels,  and  in  the 
urine,  etc.  The  germs  of  diphtheria  occasionally  remain  in  the 
throat  for  months  after  recovery,  "  diphtheria  carriers."  The 
method  of  sampling  milk  by  tasting — so  as  to  contaminate  the  milk 
by  the  mouth,  or  utensils  touching  the  mouth — is  of  course  a  source 
of  infection.  Returned  bottles  from  houses  holding  cases  of  con- 
tagious disease  are  a  menace.  Ice  cream  may  be  a  source  of  typhoid 
germs,  as  freezing  does  not  kill  them.     Typhoid  germs  also  grow 


*  Physicians  are  required  by  law  to  report  all  cases  of  infectious  disease  to 
the  local  board  of  health.  It  should  also  be  made  mandatory  that  physicians 
state  the  name  of  the  milk  dealer  supplying  the  patient  with  milk,  in  the  case 
of  every  report  of  infectious  disease,  as  is  done  in  Mt.  Vernon,  N.  Y'.  In  this 
way  endemics  originating  in  milk  contamination  with  human  infections  could 
be  readily  traced. 

f  For  "  Typhoid  Fever  Case  Card,"  see  Appendix,  p.  355. 


36  CLEAN  MILK 

in  fresh  butter,  cheese  and  buttermilk.  Inoculation  of  milk  into 
guinea  pigs,  and  growth  of  germs  on  appropriate  culture  material 
from  samples  of  milk,  may  lead  to  the  finding  of  disease  germs  in 
milk. 

Of  253  milk-borne  epidemics  collected  by  Trask,  and  occurring 
since  1895,  179  were  typhoid  fever;  51  were  scarlet  fever;  and  23 
Mere  diphtheria.  Both  the  germs  of  typhoid  and  diphtheria  may 
multiply  in  milk,  especially  if  it  is  not  properly  cooled.  Beginning 
with  78  typhoid  fever  germs  in  fresh  milk  there  were  6,000  in  24 
hours  and  440  millions  in  seven  days.  Starting  with  39  diphtheria 
germs  in  fresh  milk,  there  were  1,170  in  24  hours  and  19  millions 
at  the  end  of  a  week  (Eyre). 

There  are  certain  characteristics  of  epidemics  originating  from 
milk  which  will  lead  one  to  distinguish  them  from  those  derived 
from  other  sources.  Thus  the  sudden  onset.  A  number  of  cases 
suddenly  appear  in  one  day.  Persons  drink  the  infected  milk  at 
the  same  time  and  therefore  become  sick  at  about  the  same  time. 

Of  next  importance  is  the  fact  that  all  those  taken  sick  have 
milk  from  the  same  source.  This  does  not  mean  that  they  have 
taken  milk  from  the  same  milkman,  as  the  original  infected  milk 
may  be  mixed  with  other  milk  and  may  be  sold  by  many  milk- 
men. However,  it  is  possible  to  trace  the  source  of  the  infection 
by  looking  into  the  sources  of  supply  of  the  milkmen  distributing 
milk  to  the  sick.  To  accomplish  this  it  will  be  of  great  assistance 
if  physicians  be  required  to  report  the  name  of  the  milkman  supply- 
ing milk  to  each  contagious  case  reported  by  them.  The  decline  of 
milk-borne  outbreaks  may  be  also  more  sudden  than  is  usual  in 
others.  But  this  is  not  the  case  if  the  milk  is  constantly  contamin- 
ated, nor  if  there  are  many  new  cases  arising  from  contact  with 
the  sick.  Several  cases  are  apt  to  occur  simultaneously  in  the  same 
house  in  milk-borne  epidemics.  Then  again  those  who  drink  most 
milk  are  prone  to  be  the  patients — as  children  and  the  well-to-do. 
The  period  of  development  of  the  disease  is  likely  to  be  shorter  and 


GERMS  IN  RELATION  TO  MILK  37 

the  fatality  less  in  milk-borne  epidemics.  It  is  usually  not  possible  to 
find  the  germ  of  the  disease  in  the  infected  milk.*  This  follows  be- 
cause it  often  happens  the  milk  was  contaminated  but  for  a  short 
time,  perhaps  but  one  day.  Sometimes  the  milk  is  daily  contamin- 
ated for  a  considerable  period,  but  the  germs  may  be  greatly  diluted 
in  the  milk  or  may  be  killed  by  the  growth  of  lactic  acid  bacteria. 
In  only  one  instance  out  of  179  milk-borne  epidemics  of  typhoid 
fever  was  the  typhoid  germ  found  in  the  milk ;  and  in  but  2  out  of 
23  epidemics  of  milk-borne  diphtheria,  was  the  diphtheria  germ 
discovered  in  the  milk.  If  the  source  of  the  contaminated  milk  is 
found  and  its  use  stopped  the  epidemic  will  probably  soon  cease. 

Disease  germs  grow  best  in  pasteurized  milk,  since  they  are 
not  killed  by  the  germ-destroying  substance  in  fresh,  raw  milk, 
nor  by  the  acid  produced  by  lactic  acid  bacteria.  Readers  who  are 
particularly  interested  in  milk-borne  outbreaks  of  contagious  disease 
are  referred  to  Bull.  No.  41,  Hygienic  Laboratory  of  the  U.  S. 
Public  Health  and  Marine-Hospital  Service. 

The  lesson  which  should  be  taken  to  heart  is  that  no  sick  per- 
son or  one  coming  in  contact  with  persons  sick  with  communicable 
•diseases,  should  be  allowed  to  have  anything  to  do  with  the  hand- 
ling of  milk,  milk  utensils  or  be  permitted  entrance  to  barn  or 
dairy.  Milk  should  be  kept  in  a  room  separate  from  human  hab- 
itation, and  all  the  utensils  should  be  kept  and  cared  for  in  this 
milk  room.  Young  children  should  be  excluded  from  barn  and 
dairy,  as  they  are  much  more  prone  to  contagious  diseases  than 
adults.  Dogs  and  cats  may  be  carriers  of  germs,  dirt  and  parasites, 
and  should  also  be  kept  out  of  these  places.  The  water  used  in 
connection  with  the  dairy  should  be  examined  for  purity  by  a  com- 
petent chemist.     (See  p.  75.) 


*  And  it  is  not  worth  attempting  unless  from  the  original  sample  containing 
the  infecting  organism.  Tubercle  bacilli  in  milk  are  found  most  certainly  by 
intraperitoneal  injection  of  a  guinea  pig  with  the  centrifuged  sediment  of  40  c.  c 
of  milk  in  2  c.  c.  of  the  same  milk. 


38  CLEAN  MILK 

All  forms  of  disease  conveyed  by  germs  in  milk  to  human 
adults  are  as  nothing  in  comparison  with  the  damage  wrought  by 
germ-laden  milk  upon  infants.  Cholera  infantum,  in  fact,  is  but 
another  name  for  acute  milk  poisoning.  Practically  almost  all  the 
cases  of  summer  diarrhoea  in  babies  are  caused  by  germs  in  milk. 
These  are  probably  chiefly  of  the  putrefactive  type  which  enter 
milk  from  manure  on  the  cow.  Indeed,  in  some  localities  from  40 
to  60  per  cent,  of  the  deaths  in  infants  from  all  causes  result  from 
dirty  milk.  The  wonderful  reduction  in  the  death  rate  of  infants 
in  some  of  our  large  cities — which  is  one  of  the  remarkable  signs 
of  modern  progress — has  been  brought  about  solely  by  the  recogni- 
tion of  this  fact. 

This  reduction  is  directly-  traceable  to  the  use  of  pure  milk 
or,  where  this  is  not  obtainable,  to  pasteurizing  milk,  during  which 
the  growth  of  germs  is  killed  or  checked.  Violent  and  often  fatal 
poisoning,  resembling  cholera,  is  produced  by  a  substance  (tyro- 
toxicon)  formed  by  certain  germs  in  milk  kept  in  dirty,  covered 
vessels  during  hot  weather.  The  same  poison  has  sometimes  been 
found  in  cheese,  cream  and  ice  cream  and  has  also  caused  fatal  re- 
sults. 

Tyrotoxicon  is  a  ptomaine  or  chemical  product  due  to  the 
splitting  up  or  putrefaction  of  milk-products  by  bacteria  of  the  colon 
group.  In  ice  cream  the  number  of  germs  is  often  many  times  that 
common  to  milk  or  cream.  This  follows  because  the  cream  is  often 
pasteurized,  which  kills  the  harmless  lactic  acid  bacteria,  and  the 
cream  is  kept  at  a  low  temperature  which  allows  other  germs  to  grow 
which  are  harmful.  26  million  germs  were  found  on  an  average  in 
the  quarter  teaspoonful  in  the  examination  of  263  samples  of  ice 
cream.*  Streptococci  are  found  (Soft)  twice  as  frequently  as  in 
milk.     Storing  ice  cream  does  not  lessen  the  number  of  germs  but 


*  Ice  cream  is  usually  due  to  a  toxin  produced  by  the  paratyphoid  or  typhoid- 
colon  group  of  bacteria  (B.  enteritidis  or  B.  paratyphi),  which  may  occur  in  the 
feces  of  normal  cows.     Fecal  contamination  of  milk  is  thus  the  immediate  cause.. 


GERMS  IN  RELATION  TO  MILK  39 

renders  it  much  more  dangerous  by  giving  them  time  to  form 
ptomaines  in  it.  The  danger  of  commercial  ice  cream  lies  in  the 
dirtiness  of  the  making  and  utensils,  dirty  cream  to  start  with, 
and  finally  the  keeping  of  it  for  many  days. 

When  made  from  fresh,  unpasteurized,  clean  cream,  and  eaten 
within  a  short  time,  ice  cream  is  harmless.  About  25  per  cent,  of 
market  cream  contains  the  germs  of  tuberculosis  (see  p.  96).  These 
are  not  killed  in  ice  cream.  Therefore  ice  cream  should  be  made  of 
cream  from  tuberculin  tested  cows  or  from  freshly  pasteurized 
cream.     Much  of  the  commercial  ice  cream  is  dangerous  to  health. 

Chiefly  through  the  laudable  and  efficient  work  of  Health 
Officer  G.  W.  Goler,  M.D.,  in  supplying  certified  milk  to  the  public 
of  Rochester,  N.  Y.,  the  infant  mortality  has  been  there  reduced  as 
follows:  1887-1896,  before  milk  work  was  done,  the  average  mor- 
tality in  infants  under  1  year  in  the  month  of  July  was  1,010; 
1897-1906,  after  the  milk  work  was  begun,  the  average  mortality 
was  only  413  in  July  under  the  same  circumstances. 


40 


CLEAN  MILK 


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4i 


TABLE  II.  (b) 
SOURCES  OF  BACTERIA  THAT  GET  INTO  MILK* 
Numbers  in  this  table  refer  to  varieties  of  bacteria  in  Table  I. 


j  Largely  spherical  forms,    developing  very  slowly  In   milk. 

Inside  of  Udder.   \      *4»  r5>  r & 

Slightly  acid  forms,  3. 
[  In  some  cases  pathogenic  forms,  7,  (  8,  9).| 


COW. 


Surface  of  Cow. 


Air. 


(July,  Aug.,  Sept.) 


Milker. 


Milk  Utensils. 


Feces,  1,  2,  4,  5,  6,  8,  14,  15,  16. 

Hay  dust  2,  3,  4,  5,  6,  7,  8,  14,  15,  16.     (No.    1    found  in 

only  one  sample.) 
Grain  feeds,  1,  2,  3,  4,  5,  6,  7,  8,  10,  14,  15,  16. 
Soil  dust,  3,  4,  5,  6,  14,  15,  16. 
Air  distributed  germs  from  any  source. 
t  Indigenous  on  skin  of  cow,  1  (?),  7  (?). 

Hay  dust,  grain  feed  dust,  soil  dust,  same  as  above. 
Medium  of  distribution  for  bacteria  from  all  sources. 
Bedding  furnishes  one  of  the  largest  sources. 

1  1,  2,  3,  4,  5,  6,  7,  8,  9,  11,  12,  13,  14,  15,  16. 

I  Intestinal  disease  germs  carried  by  flies. 

f4'  5-  6'  7,  8,  9,  10,  11,  12,  13,  14,  15,  16. 

i  Hands,  clothes,  face,  hair. 

I  The  largest  source  of  disease  germs. 

f  1,  2,  3,  4,  5,  6,  7,  8,  9,  10,  11,  12,  13,  14,  15,  16. 

Water,  dust,  unsterile  cloths  or  brushes,  milk  left  in  seams, 
■j       crevices  or  in  rusty  places. 

Thoroughly  sterilized  utensils  do  not  furnish  any  bacteria 
I      in  milk. 


(b)  Taken  from  Bull.  51,  Storrs  Exper.  Sta. 

*  Bacteria  injurious  to  milk  and  disease  germs  for  man  are  indicated  by  heavy-faced  type.  Disease  germs 
for  man  are  indicated  by  heavy-faced  type  and  underscored  line. 

t  Bacteria  I  streptococci)  in  the  milk  from  an  inflamed  cow's  udder  (mastitis  or  garget)  may  cause  severe 
sore  throat  in  a  person  drinking  it,  but  not  true  diphtheria.— Author. 


CHAPTER  II 


COMPOSITION   OF   MILK  AND  CREAM   AND 
THEIR   PRODUCTS 


MILK  is  a  white,  opaque  fluid,  when  seen  in  bulk,  but  ap- 
pears transparent  in  thin  layers.  It  has  a  peculiar,  pleas- 
ant odor  and  taste  which  cannot  be  described.  They  can 
best  be  appreciated — by  comparison — when  they  are  ab- 
sent. Thus,  milk  which  has  been  heated  in  open  vessels  or  passed 
through  a  separator  loses  some  of  its  finest  flavor.  This  flavor 
resides  in  a  volatile  substance  which  escapes  in  either  process. 

Milk  has  been  called  a  vital  or  living  fluid.  This  because  of 
its  semblance  to  other  fluids  in  the  living  body  and  since  it  pos- 
sesses some  of  the  constituents  and  properties  of  these  other  fluids 
of  the  body.  Like  blood,  milk  contains  cells — as  fat  and  leucocytes 
— and  opsonins,  alexins,  and  various  ferments.  After  24  hours 
from  its  leaving  the  body  milk  becomes  dead, — that  is,  the  action  of 
the  ferments  and  germicidal  properties  are  lost. 

Chemically,  milk  is  composed  of  all  the  essentials  of  a  com- 
plete food.  That  is,  it  is  a  single  substance  which  contains  all  the 
food-elements  necessary  to  indefinitely  support  life.  These  food- 
elements  are  known  technically  as  Protcids,  Fat,  Sugar  and  Mineral 
Matters.  In  reaction  cow's  milk  is  amphoteric,  i.  c,  it  turns  red 
litmus  paper  blue,  and  blue  litmus  red. 

Proteids  in  milk  have  the  same  food  value  as  flesh  or  eggs* 

Water  is,  of  course,  the  largest  constituent  of  milk,  forming  about 

87  per  cent,  of  it. 

42 


COMPOSITION  OF  MILK  AND  CREAM  43 

The  solids  make  up  the  remainder  of  milk,  amounting  to  about 
13  per  cent,  and  comprising  the  substances  we  have  just  enumer- 
ated, proteids,  fat,  sugar  and  mineral  matters.  The  ash  or  min- 
eral matters  consists  of  salts  of  lime,  potash,  magnesium,  sodium 
and  iron  in  combination  with  chlorine,  sulphuric  and  phosphoric 
acids.  Omitting  the  mineral  matters  or  salts,  we  may,  in  a  general 
way,  remember  the  proportion  of  proteids,  fat  and  sugar  as  four 
per  cent,  of  each,  the  percentage  of  proteids  being  slightly  below 
and  that  of  sugar  slightly  above  these  figures.  The  fat  is  the  only 
one  of  these  constituents  which  varies  greatly  and  this  indeed  varies 
tremendously  (from  1.5  to  13.  per  cent.)  and  owing  to  a  great 
variety  of  circumstances  which  will  be  noted. 

If  the  fat  is  all  removed  from  milk — which  can  practically  be 
done  with  the  separator — we  have  left  the  skim  milk,  which  is 
composed  of  the  proteids,  sugar  and  water.  The  sugar  is  of  a 
kind  peculiar  to  milk  and  therefore  called  milk  sugar.  It  is  found 
in  no  other  substance  and  is  not  nearly  so  sweet  as  ordinary  or 
cane  sugar.  The  souring  of  milk  is  due  to  fermentation  of  milk 
sugar  which  takes  place  through  the  action  of  certain  germs  (lactic 
acid  germs),  which  we  have  already  mentioned  and  which  are 
always  present  in  the  cleanest  market  milk.  Since  lactic  acid  bacilli 
enter  the  milk  in  dirt,  dust,  etc.,  outside  of  the  cow,  it  is  wholly  pos- 
sible to  prevent  them  from  getting  into  milk  if  milk  is  withdrawn 
from  the  udder  through  a  tube  into  a  clean,  closed  vessel  and  does 
not  come  in  contact  with  the  air.  In  this  case  natural  souring  will 
not  occur.  These  germs  lead  to  the  breaking  up  (fermentation) 
of  the  sugar  in  milk  into  lactic  acid  (or  milk  acid).  Milk  sugar, 
sold  in  the  shops,  is  made  from  sweet  whey — a  bye-product  in 
cheese  making.  We  have  accounted  for  the  sugar  in  the  skim  milk; 
we  have  left  for  consideration  the  proteids  and  mineral  matters. 
The  proteids  are  of  three  kinds:  Casein  (or  cascinogen),  Albumin 
and  Globulin.  Casein  forms  nearly  four-fifths  of  the  proteids  (3 
per  cent,  of  milk)  and  is  that  part  of  milk  which  makes  the  curd 


44  CLEAN  MILK 

of  skim  milk,  or  the  part  of  milk  which  forms  the  bulk  of  cheese. 
The  word  caseous  means  cheesy.  The  other  kind  of  proteid  or 
albumin  remains  mostly  in  the  whey  when  milk  is  curdled.  Casein 
exists  in  the  form  of  a  neutral,  soluble  lime  compound,  calcium- 
casein,  while  the  albumin  is  in  solution,  together  with  the  mineral 
matter,  in  the  water  of  the  milk. 

In  respect  to  curdling  of  milk,  or  coagulation  of  its  casein, 
one  must  keep  in  mind  the  following  as  the  three  most  common 
causes.  ( I )  The  most  frequent — owing  to  souring — in  which 
germs  split  milk  sugar  or  lactose  into  lactic  acid.  The  lactic  acid 
breaks  up  the  lime  compound  in  which  casein  is  soluble  (forming 
calcium-lactate),  and  so  casein  appears  in  the  form  of  insoluble 
curds.  (2)  Milk,  or  the  casein  in  it,  is  curdled  by  rennet  (or 
rennin),  which  is  formed  in  the  stomach  of  man  and  animals.  (3) 
Germs  curdle  milk,  also  by  means  of  a  rennet-like  ferment  they 
produce.  The  curdling  of  milk  by  rennin  is  often  called  "  sweet 
curdling."  Rennin  splits  casein  into  two  bodies,  paracasein  and 
whey  proteid.  Here  also  the  presence  of  lime  salts  in  milk  ( calcium 
phosphate)  is  necessary  for  the  formation  of  paracasein  in  milk  by 
rennin  and  its  precipitation  as  curd.  In  cheese  making  the  develop- 
ment of  lactic  acid  causes  it  to  unite  and  form  paracasein  lactate. 
Then  the  removal  of  calcium  salts  from  paracasein  by  lactic  acid 
forming  calcium  lactate  changes  its  physical  consistency  from  a  soft 
curd  to  a  tough  plastic  curd  which  entangles  most  of  the  fat  in  the 
milk  while  pressure  squeezes  out  the  water  and  soluble  proteids  and 
sugar  as  whey.  Boiling  or  heating  milk  beyond  a 'certain  point  in- 
terferes with  curd  formation  by  rennin.  since  it  throws  down  the 
lime  salts.  Sometimes  germs  cause  curdling  in  milk  by  the  pro- 
duction of  both  acid  and  rennin. 

Globulin  exists  in  but  traces  in  ordinary  milk  but  is  present  in 
considerable  amount  in  colostrum.  It  coagulates  at  1670  F.  Lac- 
talbumin.  or  the  albumin  of  milk,  is  not  curdled  or  coagulated  by 
the  souring  of  milk,  or  by  rennet,  but  is  slightly  by  a  temperature 


Fig.  2. 


The  Constituent  Elements  of  Milk— Fat,  Serum,  and  Casein. 
(From  Swithinbank  &   Newman). 


COMPOSITION  OF  MILK  AND  CREAM 


45 


over  162  °  F.    About  1/11  part  of  the  proteids  of  milk  consists  of 

lactalbumin. 

If  milk  is  kept  a  long  while,  the  cream  (mostly  fat)  rises  to 
the  top ;  the  casein  settles  as  another  white  layer  to  the  bottom  of  the 
vessel,  while  in  between  these  is  seen  a  third  clear  layer  (serum) 
consisting  of  water,  in  which  remain  dissolved  the  mineral  matter, 
sugar,  globulin  and  albumin  (Fig.  2). 

3   The  fat  in  milk  occurs  as  the  most  minute,  microscopic  globules 
which  float  through  the  milk  and,  on  account  of  their  buoyancy,  rise 
more  or  less  quickly  to  the  surface  and  there  form  cream.     These 
minute  droplets  of  fat  are  apparently  surrounded  by  a  wonderfully 
thin  pellicle  or  covering  which  has  been  thought  to  consist  of  a  layer 
of  casein  adhering  by  capillary  attraction.    This  surrounding  mem- 
brane does  not  exist,  according  to  recent  research,  milk  being  a 
natural  emulsion.     The  fat  globules  vary  greatly  in  size,  some  being 
six  times  the  diameter  of  others.     They  average  about  1-5,000  of 
an  inch  in  diameter,  and  one  drop  of  milk  no  larger  than  a  pinhead 
may  contain  1,500,000  fat  globules.     The  difference  in  the  S1ze  of 
the  fat  globules  in  different  breeds  of  cows  and  in  human  milk  is 
shown  by  Gilbert's  table.    A  micron  =  1/25,000  of  an  inch. 
Size  of  Fat  Globules  in  Different  Kinds  of  Milk. 


Human 

Jersey 

Guernsey 

Ayrshire 

Holstein 

Average  diameter  in  microns  or  ft.. 
Average  variation  in  microns  p.. .  ■ 

2.9 
1.2 

2.8 
•9 

2.6 

•85 

2.1 
.76 

2.0 
.66 

The  larger  globules  of  fat  are  most  buoyant  and  rise  to  the 
surface;  only  the  smallest  remain  in  skim  milk.  The  fat  globules 
are  larger  in  some  breeds  of  animals,  particularly  the  Jerseys,  and 
the  cream  therefore  rises  more  rapidly  and  completely.  The  size  of 
fat  globules  in  mixed  milk  varies  from  2  to  30  microns.  As  the 
lactation  period  advances  the  globules  diminish  2  or  3  times  m  size 
and  increase  2  or  3  times  in  number.     While  there  are  breed  dif- 


46  CLEAN  MILK 

ferences,  in  the  size  of  the  globules,  there  are  great  individual  differ- 
ences in  the  same  breed.  The  fat  globules  are  arranged  in  groups 
or  clumps  in  milk  instead  of  being  uniformly  scattered  throughout 
the  fluid.  This  is  of  considerable  practical  importance,  for  milk 
which  has  been  separated  or  heated  (pasteurized)  does  not  cream 
so  well  because  the  clumps  of  fat  globules  are  broken  up  and  so  do 
not  rise  so  quickly  or  completely.  For  example,  milk  is  passed 
through  a  separator  revolving  at  the  rate  of  1,200  revolutions  a 
minute,  not  fast  enough  to  separate  the  milk  from  the  cream  (which 
is  sometimes  done  to  remove  the  dirt  from  milk  or  to  "  clarify  "  it), 
and  the  milk  is  bottled.  The  cream  will  rise  from  this  milk  slowly 
and  incompletely,  and  the  cream,  when  it  has  risen,  will  appear  so 
thin  that  a  twenty  per  cent,  cream  may  not  seem  thicker  nor  richer 
than  rich  milk. 

Pasteurizing  milk  will  cause  much  the  same  result,  if  the  milk 
is  subjected  to  considerable  agitation  in  the  process. 

If  milk  is  cooled  within  a  few  moments  of  pasteurization  to 
400  F.  and  bottled  immediately  the  cream  will  rise  quickly  into  a 
smaller  and  denser  mass  than  on  unheated  milk,  but  showing  a  good 
cream  line. 

The  mineral  matter  in  milk  comprises  a  very  small  amount 
of  variety  of  salts  and  altogether  they  do  not  form  quite  one  per 
cent,  of  the  whole  milk. 

The  following  table  perhaps  fairly  represents  the  composition 
of  what  might  be  called  average  milk  *  from  a  large  herd  of  average 
cows  of  various  breeds : 

Per   Cent- 

Water  87.00 

Fat    400 

Proteids  3-30 

Sugar    4-95 

Mineral    Matter     0.75 

*  The  U.  S.  Pure  Food  Act  of  1906  fixes  the  standard  for  milk  as  fol- 
lows: Solids  not  fat,  8.5  per  cent.;  milk  fat,  3.25  per  cent.;  milk  solids,  total, 
11.75  per  cent.     Skimmed  milk  to  contain  9.25  per  cent-  of  total  solids. 


COMPOSITION  OF  MILK  AND  CREAM 


47 


Average  Composition  of  Woman's  Milk. 


Proteids    

Fat    

Milk  sugar  . . . 
Mineral  Matter 
Water    


Per  Cent 
i-5 
3-3 

6.8 

0.2 

88.2 


The  chief  differences  between  cow's  and  human  milk  are  that 
the  proteids  exist  in  much  larger  proportion  as  albumin  in  human 
milk  and  that  human  milk  is  subject  to  greater  daily  variations  in 
composition.  Also  there  are  ferments  in  human  milk  (  anxi- 
olytic or  starch  digesting,  and  salol-splitting)  which  are  not  found 
in  cow's  milk.* 

We  will  now  consider  in  detail  the  various  circumstances 
which  modify  the  composition  of  milk.  It  is  a  curious  fact  that 
the  character  of  the  food  of  cows  has  little  influence  upon  the 
composition  of  milk  although  it  affects  tremendously  the  yield  of 
milk.  The  composition  of  the  milk  is  dependent  on  the  cow  and 
breed,  and  is  as  much  a  characteristic  as  her  color  and  as  difficult 
to  change.  The  following  table  illustrates  the  average  composition 
of  the  milk  of  herds  of  different  breeds  of  cows: 


t  Durham 
or  Short- 
horn 

Devon 

Ayrshire 

Holstein- 
Friesian 

Jersey 

Brown 

Swiss 

Common 
Native 

Fat 

Sugar 

Proteids 

Min'al  M't'rs.. 

4.04 
4.84 
4-17 
0-73 

4.09 

4-32 
4.04 

073 

3-89 
4.41 
4.01 

0-73 

2.88 
4-33 
3-99 
0.74 

3-58 

073 

4.00 
4-3° 
4.00 
0.76 

3-69 
4-35 
4.09 
0.76 

According  to  the  statutes  of  the  various  states, £  the  required 
standard  of  composition  of  milk  differs  to  a  slight  extent,  but  as 
much  as  three  per  cent,  of  fat  is  demanded  in  every  state,  except 


*  There  is  much  more  lecithin  in  the  fat  of  human  milk  and  the  curd  formed 
in  the  stomach  is  softer  than  that  of  cow's  milk. 

f  Abstract  of  tables  compiled  by  Mr.  Gordon,  of  Walker-Gordon  Labo- 
ratory. The  figures  for  Holstein-Friesian  in  the  case  of  fat  are  rather  low; 
3.2  per  cent,  fat  would  be  nearer  the  minimum  average. — K.  W. 

t  Laws  in  force  in  June,  1900. 


48  CLEAN  MILK 

Rhode  Island,  and  solids  amounting  to  twelve  per  cent.,  in  most 
states,  and  as  high  as  thirteen  per  cent,  in  some. 

The  legal  requirements  for  fat  and  total  solids  are  often  too 
high  and  unfair  to  owners  of  cows  yielding  milk  below  these 
standards  or  to  those  shipping  milk  which  has  not  been  thoroughly 
mixed.  The  Massachusetts  standard  requires  that  in  the  fall  and 
winter  months  milk  shall  contain  not  less  than  3.7  per  cent,  fat, 
nor  less  than   13  per  cent,  of  total  solids. 

This  works  harm  to  owners  of  Holstein-Friesians,  especially, 
as  these  cows  often  yield  milk  below  the  legal  standard  and  yet  it 
is  milk  best  suited  for  infants.* 

The  composition  of  milk  varies  according  to  the  period  of 
milking,  the  milk  growing  richer  in  fat  and  the  fat  globules  larger 
as  milking  advances,  the  last  of  the  milking  or  "  stoppings  "  being- 
very  rich. 

Per  Cent. 
Fat. 

tFore    Milk    3-8 

Middle    Milk    6.74 

Strappings    8. 12 

The  reason  for  this  is  said  to  be  that  the  fat  globules  are  retarded 
by  friction  on  the  sides  of  the  milk  ducts  in  the  udder  and  are 
forced  out  in  abundance  towards  the  last  of  milking.  The  per- 
centage of  the  other  solids  remains  practically  unchanged  at  differ- 
ent periods  of  milking. 

It  is  a  curious  fact  that  when  the  calf  sucks  the  cow,  the  last 
of  the  milk  appears  to  be  much  poorer  in  fat  than  the  first  part. 

If  cows  are  milked  at  frequent  intervals  the  yield  of  milk  is 
greater  and  the  percentage  of  fat  larger.  The  milk  is  formed  in 
the  cells  of  the  udder  and  is  conducted  through  numerous  fine  tubes 
of  increasing  size  until  it  empties  into  a  reservoir  (holding  about 
one-half  pint  on  an  average)  connected  with  the  upper  end  of  the 

*The  standard  for  fat  content  must  not,  however,  be  removed  or  made  too  low 
so  as  to  encourage  production  of  low  grade  milk.  Holstein  milk  may  be  much 
improved  by  breeding,  see  p.  68. 

t  Dr.  Charles  Harrington's  analysis. 


COMPOSITION  OF  MILK  AND  CREAM  49 

canal  or  opening  in  the  centre  of  each  teat.  There  are  therefore 
four  milk  cisterns  in  the  udder,  one  for  each  teat.  It  is  probable 
that  when  the  udder  has  become  accustomed  to  hold  in  its  ducts  and 
cisterns  a  certain  quantity  of  milk  it  will  for  a  time  secrete  nearly 
the  same  amount  during  each  interval  between  milkings.  After  a 
while,  however — if  the  cow  is  milked  more  frequently  than  usual — 
the  udder  will  not  continue  to  secrete  the  same  amount  of  milk  and 
the  exceptional  quantity  obtained  by  frequent  milkings  will  cease. 
Milking  three  times  daily  is  practiced  in  some  parts  of  Europe,  but 
milking  more  than  twice  in  the  twenty-four  hours  is  rarely  con- 
sidered economical  in  the  United  States,  and  is  not  done  except  in 
the  case  of  very  heavy  milkers  or  in  cows  newly  calved. 

Milk  is  formed  continuously  all  the  time  and  not  chiefly  at 
milking  time,  as  has  been  thought. 

Milking  at  the  same  hours  twice  daily,  as  at  five  a.m.  and  five 
p.m.,  gives  the  same  amount  of  milk  at  each  milking.  Milking  has 
no  effect  on  milk  formation.  Frequent  milking  increases  the  milk- 
yield  simply  by  more  complete  emptying  of  the  udder.  The 
longer  the  interval  between  milking  the  larger  the  quantity  of 
milk  and  the  poorer  the  quality  of  the  milk ;  the  shorter  the 
interval,  the  smaller  and  richer  the  yield  of  milk.  In  the  summer 
the  nights  are  short  and  therefore  the  morning  milking  is  apt  to 
be  richer.  In  winter  the  reverse  is  true  and  the  night  milking  is 
likely  to  be  the  richer. 

The  following  analyses  of  the  milk  of  one  herd  at  the  Delaware 
Experiment  Station  show  this : 

Night  Milk  Morning  Milk. 

Per   Cent.    Fat.  Per   Cent.   Fat. 

July  24th 3.76  4.67 

February  5th    4.56  3.53 

The  season  of  the  year  influences  the  composition  of  milk. 
Tn  the  summer  the  percentage  of  fat  and  other  solids  is  lowest.     In. 
the  winter  months  the  milk  is  richest  in  fat  and  solids  not   fat. 


50  CLEAN  MILK 

Thus  in  the  months  of  November,  December  and  January,  the  solids 
may  average  13.36  per  cent,  and  the  fat,  4.16  per  cent.;  while  in 
May,  June  and  July  the  solids  may  average  12.68  per  cent,  and  the 
fat  3.82  per  cent. 

The  changes  in  the  composition  of  one  cow's  milk  are  great 
and  may  be  brought  about  through  various  influences,  as,  for 
instance,  fright,  excitement,  rough  handling,  change  of  milker, 
exposure  to  bad  weather,  unfamiliar  surroundings,  sudden  change 
in  the  character  of  food,  and  irregularity  in  time  of  milking.  It 
follows  without  saying  that  all  these  unfavorable  influences  are,  as 
far  as  possible,  to  be  avoided. 

In  an  analysis  of  hundreds  of  samples  of  milk  from  single  cows, 
Farrington  found  that  in  the  case  of  a  Holstein  there  was  as  much 
difference  between  the  highest  and  lowest  percentage  of  fat  as  be- 
tween 6.6  per  cent,  and  1.5  per  cent.,  while  in  the  case  of  the  Jersey 
— in  which  sudden  changes  are  most  common — the  highest  was  12.3 
per  cent,  of  fat ;  the  lowest,  2.9  of  fat.  The  variations  in  the  per- 
centage of  the  other  solids — proteids,  milk  sugar  and  salts — are 
very  slight,  especially  of  milk  sugar. 

The  mixed  milk  of  a  large  herd  is  pretty  constant  in  composi- 
tion except  as  influenced  by  the  season  and  by  the  times  the  cows 
calve.  For  the  composition  of  milk  varies  at  different  times  in  the 
milking  period.  The  milking  period  of  the  cow  lasts  about  323  days 
on  the  average  after  calving,  she  going  dry  about  eight  weeks 
before  she  calves  again.  The  interval  between  two  calving  days 
averages  about  398  days. 

In  cows  which  are  well  tended  and  fed  the  percentage  of  fat 
increases  as  the  milking  period  progresses,  so  that  the  milk  is  richer 
at  the  close  than  at  the  beginning  of  the  period  of  milking. 

The  period  of  heat  in  a  cow  is  often  accompanied  by  a 
diminished  yield  of  milk  which  is  poor  in  fat  (so  that  the  fat  may 
be  reduced  to  one  per  cent.),  and  the  milk  curdles  on  boiling.  The 
fat  after  this  period  is,  however,  proportionately  increased  over  that 


COMPOSITION  OF  MILK  AND  CREAM  51 

usually  present.  When  cows  are  constantly  in  heat  (nymphomania, 
"  bullers  ")  the  milk  yield  is  diminished  and  the  composition  may 
Tje  altered.  Abortion,  while  lowering  the  amount  of  milk,  does 
not  influence  the  composition — unless  the  cow  is  otherwise  sick. 

The  milk-yielding  capacity  of  cows  generally  increases  up  to 
the  eighth  year  of  age,  and  then  decreases.  With  the  decrease  of 
yield  there  appears  to  be  often  a  decrease  in  fat  and  total  solids  in 
the  milk.  It  was  thought  at  one  time  that  the  spaying  of  cows 
would  prove  of  advantage  in  sustaining  the  yield  and  improving  the 
richness  of  their  milk,  but  it  has  not  been  found  so  in  practice, 
except  in  those  animals  which  are  constantly  in  heat  owing  to 
disease. 

The  dehorning  of  cattle  is  said  to  improve  the  yield  of  milk, 
but  there  can  be  no  conceivable  reason  for  this  other  than  in  the 
freedom  from  fighting  and  wounds  which  this  practice  accomplishes. 

The  composition  of  milk  is  of  great  importance  in  that  the 
value  of  milk  depends  upon  the  amount  of  fat  it  contains,  other 
things  being  equal. 

It  has  now  become  the  custom  for  creameries  in  most  parts  of 
the  country  to  pay  a  sum  for  milk  proportionate  to  the  amount  of 
butter-fat  it  contains  as  estimated  by  the  use  of  the  Babcock  machine 
at  certain  stated  intervals.  First-class,  pure  or  "  certified  "  milks 
now  sold  for  an  advanced  price  in  cities  should  contain  a  high 
average  of  fat,  unless  sold  exclusively  for  infants'  use.  Such  milk 
often  averages  five  per  cent.  Then  again  it  is  for  the  farmer's  ad- 
vantage, if  he  is  to  produce  a  high  quality  of  milk,  that  he  know  the 
composition  of  the  milk  of  all  his  individual  cows  so  that  the  poorer 
ones  may  be  weeded  out.  This  may  be  accomplished  by  the  use  of 
a  Babcock  machine  on  the  farm  (see  p.  193). 

Colostrum  (common  name  beastings,  etc). — Colostrum  is  the 
milk  secreted  immediately  after  calving  and  differs  very  markedly 
in  composition  from  ordinary  milk.  Colostrum  is  of  a  slightly 
yellowish  or  brownish  color  and  has  a  peculiar  smell,  a  slimy  con- 


$2  CLEAN  MILK 

sistency  and  salty  taste.  The  proteids  are  at  first  large  in  amount 
and  represent  albumins  and  globulins  (9  to  10  per  cent.)  rather  than 
casein.  For  this  reason  the  milk  becomes  curdled  on  boiling  and 
this  is  a  test  for  colostrum ;  if  it  curds  on  boiling  it  is  unfit  for  use. 

The  sugar  in  colostrum  is  not  milk  sugar,  but  represents  sev- 
eral other  varieties.  The  percentage  of  fat  is  variable,  while  that 
of  mineral  matter  is  high.  Colostrum  usually  separates  into  two 
layers  on  standing.  Under  the  miscoscope  there  are  to  be  seen  in 
it  very  large  globules  of  fat,  called  "  colostrum  corpuscles,"  and 
these  are  characteristic  of  this  form  of  milk.  The  colostrum  varies. 
in  composition  from  one  milking  to  another  after  calving,  becoming; 
more  and  more  like  ordinary  milk. 

The  following  analysis  will  give  an  idea  of  its  composition  : 

Per    Cent. 

Water    787 

Fat    40 

Proteids     14.8 

Sugar    15 

Mineral  Matters 1.0 

1 00.0 

While  the  proteids  in'colostrum  are  so  soluble  that  they  can  be 
absorbed  by  the  calf  without  any  tax  on  its  digestion,  and  appear 
to  start  up  digestion  in  this  animal,  yet  colostrum  is  not  wholesome 
for  man  for  from  five  to  twenty  days  after  calving.  Legal  require- 
ments vary  somewhat,  but  usually  demand  that  cows'  milk  shall 
not  be  sold  for  fifteen  days  before,  nor  from  five  to  twelve  days 
after  the  calving  of  the  cow  supplying  the  milk. 

The  boiling  test,  referred  to  above,  will  show  when  the  milk 
is  fit  for  human  consumption.  The  milk  is  not  fit  for  churning* 
until  five  days  after  calving,  nor  from  ten  to  twelve  days  for  making- 
cream  cheese. 

Colostral  milk  and  the  milk  obtained  from  the  cow  within 
fifteen  days  before  calving  have  produced  disease  in  man.     Colos- 


COMPOSITION  OF  MILK  AND  CREAM 


53 


trum  has  caused  high  fever,  inflamed  throat  and  mouth,  which  were 
-covered  with  small  sores  or  ulcers;  while  milk  from  cows,  with- 
drawn a  few  days  before  calving,  is  sometimes  the  source  of  colic 
and  diarrhea  in  the  human.  When  cows  give  less  than  three  quarts 
daily  their  milk  is  unfit  for  human  consumption.  The  milk  from  a 
cow  immediately  after  calving  frequently  contains  blood,  coming; 
from  that  which  soils  the  udder  and  tail  after  flowing  out  of  the 
vagina. 


CHAPTER  III 


MILK  PRODUCTS 


IT  is  a  curious  fact  that  the  quantity  of  cream  obtained  from 
setting  rich  or  poor  milk  is  about  the  same  for  rich  as  for  poor 
milk,  but  the  cream  from  the  poor  milk  is  much  thinner  and  con- 
tains less  fat.  As  seen  in  a  glass  quart  milk-jar,  the  layer  of 
cream  forms  almost  a  quarter  of  the  bulk  of  the  contents  of  the 
bottle,  at  first,  but  after  twenty-four  hours  or  longer  the  layer  of 
cream  becomes  less,  owing  to  the  crowding  together  of  fat  globules. 
When  cream  rises  in  tall  vessels  it  contains  a  great  deal  more  fat 
in  its  upper  than  in  its  lower  layers. 

In  fact,  of  the  cream  which  rises  in  a  bottle  of  milk,  the  upper 
ounce  contains  as  much  sometimes  as  25  per  cent,  of  fat,  while  the 
fat  in  the  cream  regularly  diminishes  until  at  the  lowest  part  of 
the  layer  of  cream,  which  can  be  seen  as  a  sharp  line  above  the  milk,. 
the  percentage  of  fat  is  not  quite  10  per  cent.  The  cream  line  in 
bottled,  pasteurized  milk  is  apt  to  be  poorly  defined  since  the  natural 
clumps  of  fat  globules  in  the  milk  are  broken  up  by  pasteurization 
and  the  cream  rises  incompletely.  This  is  a  serious  disadvantage 
if  it  is  desired  to  remove  the  cream  for  infant  feeding  or  other 
purposes.  As  we  have  already  said,  the  higher  the  creaming  tem- 
perature the  richer  will  be  the  cream,  and  for  this  reason  the  quantity 
of  it  will  be  much  less  than  from  the  same  amount  of  milk  which 
is  set  at  a  low  temperature.  For  the  lower  the  cream  temperature, 
especially  at  the  end  of  the  creaming  period,  the  greater  will  be 
the  amount  of  cream  and  the  thinner  will  it  be  owing  to  the  greater 
quantity  of  water  in  it.     Milk  which  has  been  watered  throws  tip* 

54 


MILK  PRODUCTS  55 

its  cream  much  more  rapidly  than  other  milk.  This  accounts  for 
the  custom,  with  many  farmers,  of  pouring  a  considerable  amount 
of  cold  water  into  their  milk  cans  when  they  wish  to  secure  cream 
quickly  for  their  own  use. 

Separator  Cream 

By  the  use  of  a  separator,  which  consists  of  a  rapidly  whirling 
steel  bowl  (5.000  revolutions,  more  or  less,  per  minute),  the  heavier 
portions  of  the  milk — the  skim  milk  and  dirt — are  thrown  against 
the  inside  of  the  rotating  bowl  by  centrifugal  force,  while  the  lighter 
portion — the  cream — remains  near  the  centre.  The  dirt  sticks  to 
the  side  of  the  bowl,  where  it  forms  a  tough,  sticky  layer  known  as 
separator  slime.  This  separator  slime  is  not  composed  by  any 
means  of  filth  entirely,  because  a  good  part  of  it  is  made  up  of  the 
proteid  constituents  of  the  milk  (curd)  ;  one  authority  says  that 
nine-tenths  of  the  dried  slime  is  formed  of  this  natural  product 
of  the  milk.  That  there  is  a  great  amount  of  filth  in  ordinary 
market  milk  has  been  abundantly  shown.  It  has  been  estimated 
that  the  citizens  of  New  York  eat  daily  ten  tons  of  barn  filth  and 
refuse  in  their  milk.  This  amount  is  probably  exaggerated,  since 
Berlin  is  said  to  furnish  its  inhabitants  but  300  pounds  of  cow 
dung  in  its  daily  milk-supply,  and,  allowing  a  wide  margin  for  our 
native  progressiveness,  we  could  hardly  be  credited  with  beating 
the  Germans  so  tremendously  in  this  international  filth  contest.  In 
the  separator  slime  are  to  be  found,  in  addition  to  the  cheesy  matter 
from  milk,  manure,  fodder,  hairs,  particles  of  skin,  insects,  down 
from  birds,  threads  from  clothing,  bits  of  bedding,  cobwebs,  bristles, 
soil,  etc.,  and  large  quantities  of  germs.  The  slime  forms  from 
.04  to  .3  of  1  per  cent,  of  the  weight  of  the  new  milk,  depending 
upon  its  original  state  of  cleanliness.*  The  use  of  the  separator  is 
superior  to  all  other  methods  of  obtaining  cream  on  account  of  its 


*  Separator  slime  should  be  burned  to  destroy  tubercle  bacilli  in  it.     It  should 
never  be  used  to  feed  swine. 


56  CLEAN  MILK 

power  to  more  rapidly  and  thoroughly  extract  fat  from  milk.  Thus 
it  shortens  the  period  for  growth  of  germs  permitted  by  the  older 
methods  of  creaming,  and — to  some  extent — removes  germs  already 
present  in  the  milk.  The  cream,  however,  will  be  found  to  contain 
as  many  or  more  germs  as  the  milk  did  before  separation,  although 
the  skim  milk  leaving  the  separator  may  show  one-third  to  one-half 
less  germs  in  pretty  clean  milk,  but  in  filthy  milk  the  number  of 
germs  after  separation  is  practically  unaltered.  Recent  experi- 
ments show  that  of  the  germs  present  in  whole  milk  before  separa- 
tion, 47  per  cent,  appear  in  slime.  29  per  cent,  in  milk  and  24  per 
cent,  in  cream  after  separation.  ( Eckles  &  Barnes,  Iowa  Sta. 
Bull.,  1902.)  Cream,  after  separation,  must  therefore  be  rapidly 
cooled  down  from  the  high  temperature  of  separation  (86°  F.)  to 
400  F.  in  order  to  prevent  the  growth  of  germs  which  have  not 
been  removed  to  any  great  degree  by  the  process. 

The  use  of  the  separator  to  free  milk  of  germs  is  not  a  success, 
although  this  method  has  been  practiced  in  large  cities  to  cleanse 
or  "  clarify  "  milk. 

None  of  the  disease  germs  occasionally  present  in  milk  is  cer- 
tainly removed  by  separation.  When  used  to  cleanse  milk  the 
separator  is  run  at  a  comparatively  low  speed  so  as  not  to  separate 
the  cream  from  the  milk,  but  sufficient  to  remove  much  of  the  tilth 
and  therefore  the  so-called  animal  odor.  Although  there  may  be 
an  improvement  in  the  flavor  and  odor  of  the  milk,  it  will  not  keep 
any  longer,  showing  that  germs  are  not  removed.  Filtering  milk 
by  various  devices  has  about  the  same  value. 

The  filth  and  insoluble  dirt  are  removed  more  or  less  com- 
pletely, and  the  -taste  and  odor  improved  thereby,  but  dirt,  as 
manure,  which  is  dissolved  in  the  milk  and  the  essential  contamina- 
tion— the  germs — are  not  removed.  For,  as  Professor  Conn  lias 
pointed  out,  the  germs  are  so  minute  and  so  much  smaller  than  the 
fat  globules  that  it  would  be  necessary  to  employ  a  filter  which 
would  remove  all  the  fat  in  the  milk  in  order  to  catch  the  germs  in 
the  filter. 


MILK  PRODUCTS  57 

Dr.  Seibert  states  that  by  filtering  milk  through  one-half  inch 
of  compressed  cotton  seven-eighths  of  the  bacteria  are  removed. 
This  is  a  very  slow  process  and  some  fat  is  removed  by  it. 

Complete  separation  of  milk  into  cream  and  skim  milk  is  some- 
times done  for  cleansing  purposes,  the  skim  milk  and  cream  being 
reunited.  Many  physicians  believe  that  milk  thus  treated  is  often 
the  cause  of  indigestion  in  infants. 

Neither  these  nor  any  other  methods  will  make  dirty  milk  clean. 

Contamination  of  milk  begins  at  the  farm,  and  only  at  the 
farm  can  it  be  eradicated.  Absolute  cleanliness  with  respect  to 
milking  and  everything  which  comes  in  contact  with  the  milk, 
together  with  immediate  cooling  to  below  500  F.,  will  alone  insure 
success.  The  importance  of  germs  in  relation  to  milk  is  as  great 
as  to  the  operating  surgeon,  and  the  amazing  progress  in  both 
surgery  and  dairying  is  due  chiefly  to  the  appreciation  of  this  fact. 

Exclusive  of  fat,  the  percentage  of  the  other  constituents  of 
milk — proteids,  sugar  and  mineral  matters — is  about  the  same  in 
cream  as  in  milk,  unless  the  cream  be  of  unusual  richness.  For  the 
same  reason,  the  composition  of  skim  milk  is  about  the  same  as 
Avhole  milk,  the  fat  excepted.  The  fat  is  practically  absent  from 
separator  skim  milk  and  is  present  in  skim  milk,  from  which  the 
cream  has  been  removed  by  hand,  to  the  extent  of  one-half  to 
one,  or  even  one  and  one-half  per  cent.  The  following  tables 
illustrate  these  statements : 

Composition  Composition  Composition  Composition 

of    milk  of  20(/'c  Cream  of  25' <■  Cream  of  67%  Cream 

Per  Cent.  Per  Cent.  Per  Cent.  Per  Cent. 

Fat 4-00  20.00  25.00  67.00 

Sugar    4.50  4.8  4.8  2.2 

Proteids    3.5  305  3-2  1-2 

Mineral  matters   .     07  0.6  0.7  0.1 

Composition  of  Composition  of 

Hand-skimmed  Milk  Separator  Skim  Milk 

Per  Cent.  Per  Cent.  Per   Cent- 

0.12  to  0.1 

Fat    0.75  (hand)  (power) 


58  CLEAN  MILK 

The  cream  from  set-milk  contains  90  to  99  per  cent,  of  the 
germs  which  were  present  in  the  whole  milk,  because  in  rising  the 
fat  globules  entangle  the  germs  and  carry  them  along  to  the  surface. 
These  germs  are  chiefly  made  up  of  the  varieties  which  cause  the 
souring  of  milk  or  cream  (lactic  acid  bacilli),  and  these  increase 
for  forty-eight  hours  at  favorable  temperatures — 6o°  to  700  F. — 
in  cream,  and  then  gradually  die  out,  owing  to  the  unfavorable  in- 
fluence of  the  acid  formed  in  souring,  so  that  in  a  week  few  remain. 
During  the  first  few  hours  there  are  to  be  found  a  great  variety  of 
germs  in  milk  and  cream,  but  the  lactic  acid  bacilli  crowd  these  out, 
because  they  grow  so  much  more  readily  than  do  the  other  kinds  of 
germs,  and  at  the  end  of  forty-eight  hours  there  may  be  as  many 
as  500,000,000  lactic  acid  germs  to  the  quarter  teaspoonful.  Butter 
is  commonly  made  from  cream  which  has  "  ripened."  By  ripening 
is  meant  the  changes  which  occur  in  cream  owing  to  the  growth  of 
germs  in  it  during  the  process  of  souring. 

The  ripening  of  cream  may  be  compared  to  the  change  which 
takes  place  in  grape  juice  when  it  turns  to  wine.  Both  changes — 
in  the  grape  juice  and  cream — are  brought  about  by  fermentation, 
and  fermentation  is  simply  a  term  for  describing  the  changes — 
chemical  and  physical — which  occur  in  a  substance  owing  to  the 
action  of  germs  *  and  their  products  upon  it. 

In  the  ripening  or  fermentation  of  cream  the  germs  alter  the 
character  of  the  cream  and  supply  bodies  which  give  to  the  butter 
its  peculiar  flavor  and  improve  its  keeping  qualities.  Butter  made 
from  fresh  cream  has  less  flavor  and  does  not  keep  well.  The 
sour  milk  germs  give  butter  part  of  its  flavor,  but  the  miscellaneous 
germs  which  are  crowded  out  by  the  former  also  are  responsible 
for  much  of  the  flavor.  In  this  country  the  popular  palate  requires 
a  much  stronger  flavored  butter  than  the  European  taste,  which 
regards  our  butter  as  rank  in  flavor.  Therefore  abroad  it  is  often 
customary  to  pasteurize  fresh  cream  to  kill  the  miscellaneous  germs 


*  Or,  rarely,  to  the  action  of  ferments  or  enzymes. 


■MILK  PRODUCTS  59 

and  add  the  sour  milk  germs  in  the  form  of  a  "  starter,"  thus  getting 
a  butter  made  from  ripened  cream,  but  avoiding  the  stronger 
flavor  caused  by  the  miscellaneous  germs.  The  flavor  and  aroma  of 
butter,  then,  depend  upon  the  varieties  of  germs  in  cream.  Butter 
is  thought  to  possess  the  finest  flavor  in  May  and  June  because  at 
this  season  the  greatest  variety  of  germs  flourish  in  the  milk. 

The  chief  reason  why  butter  is  so  much  better  from  certain 
dairies  than  others  is  because  the  better  dairies  are  the  homes  of 
special  kinds  of  germs,  which  give  butter  a  good  flavor  and  aroma, 
while  in  the  others — owing  to  want  of  cleanliness  of  the  cows,  barns, 
milk  rooms,  employees  or  utensils — special  germs  of  filth  which  are 
unfavorable  to  good  dairy  products  come  to  occupy  the  premises. 

The  action  of  the  germs  is,  then,  the  essential  factor  in  the 
production  of  good  butter,  as  in  all  other  departments  of  dairying. 
As  we  have  pointed  out,  the  lactic  acid  germs,  while  in  the  minority 
in  the  milk  just  drawn  from  the  cow,  soon  gain  ascendancy  by 
multiplying  in  milk  or  cream,  and  it  is  to  this  type  of  germ  that  the 
ripening  of  butter  and  of  cheese  is  chiefly  due. 

We  have  also  shown  that  to  the  miscellaneous  germs  in  milk 
and  cream  butter  owes  some  of  its  flavor.  But  as  some  of 
these  are  deleterious  to  flavor  and  aroma,  and  are  not  to  be  de- 
pended upon,  the  endeavor  has  been  made  to  employ  only  the  lactic 
acid  bacilli  to  ripen  cream.  These  are  present  in  pure  culture ;  that 
is,  they  form  the  only  type  of  germ  in  the  commercial  starters, 
which  may  be  bought  in  market  in  various  shapes,  as  bottles  of  milk, 
pastes,  powders  and  pellets,  all  merely  vehicles  for  the  growth  and 
preservation  of  lactic  acid  germs.  This  starter  is  added  to  fresh 
cream  to  ripen  it.  If  the  cream  is  already  sour  it  is  useless  to  add 
a  starter.  It  is  best  to  first  heat  cream  to  1550  F.,  to  destroy  the 
miscellaneous  germs,  before  adding  the  starter  containing  the  lactic 
acid  germs,  but  in  this  country,  where  the  added  flavor  caused  by 
the  miscellaneous  germs  is  desired,  the  starter  is  more  commonly 
added  to  fresh  cream.    The  starters  which  were  first  used  consisted 


60  CLEAN  MILK 

simply  of  a  quantity  of  sour  milk  or  cream  containing  a  great  num- 
ber of  germs,  suitable  for  ripening  cream,  which  was  added  to  fresh 
cream  to  quickly  sour  and  ripen  it,  especially  in  cold  weather.  These 
are  called  natural  starters,  and  are  still  used  extensively.  To  pre- 
pare such  a  starter  the  milk  is  withdrawn  from  the  cow  in  the  most 
cleanly  manner;  the  milk  is  then  separated  and  the  skim  milk  is 
collected  in  an  absolutely  clean  vessel  and  set  aside  at  a  temperature 
of  6o°  to  yo°  F.  to  sour.  This  sour  milk  may  contain  all  sorts  of 
germs,  but  if  it  is  clean  there  are  apt  to  be  few  miscellaneous  germs 
and  these  are  likely  to  be  crowded  out  by  the  growth  of  the  lactic 
acid  germs,  so  that  the  result  may  be  almost  as  pure  a  culture  or 
collection  of  lactic  acid  bacilli  as  is  found  in  the  commercial  starters. 
We  quote  the  following  from  Farrington : 

The  foundation  material  for  both  kinds  of  starters  is  usually  skim  milk. 
This  is  first  freed  from  most  of  its  bacteria  by  heating  it  to  1S0  deg.  F.  or 
above,  for  at  least  one-half  hour.  It  is  a  good  plan  to  keep  this  hot  milk  well 
stirred  and  covered  while  it  is  being  heated.  After  this  period  of  heating,  the 
skim  milk  is  cooled.  The  cooling  is  usually  done  by  setting  the  can  of  hot 
skim  milk  into  cold  water.  The  quicker  it  is  cooled  the  better.  When  the 
temperature  of  the  skim  milk  reaches  80  deg.  F.,  it  is  then  in  condition  to 
receive  either  the  pure  culture  which  has  been  brought  from  the  dealer,  or 
the  sour  milk  which  has  been  selected  and  allowed  to  sour  naturally. 

The  so-called  commercial  starters  are  made  by  adding  to  about  a  gallon 
of  this  skim  milk  a  small  quantity  (about  an  ounce)  of  the  pure  culture  which 
has  been  brought  from  a  dealer  in  this  material.  After  the  pure  culture  has 
been  added  to  the  skim  milk  the  mixture  is  kept  at  a  temperature  of  about 
80  deg.  F.  until  the  skim  milk  has  become  soured  by  the  pure  culture  bacteria. 
This  preparation  is  sometimes  called  "  startoline,"  and  it  may  amount  to 
about  four  quarts  of  sour  milk.  This  is  added  to  a  larger  quantity  of  pasteur- 
ized skim  milk,  which  has  been  prepared  by  heating  and  cooling  as  previously- 
described,  and  the  mixture  is  allowed  to  stand  at  a  temperature  near  80  deg. 
until  it  becomes  sour  and  has  an  acidity  of  about  six-tenths  of  one  per  cent.* 
If  the  cream  in  which  the  starter  is  to  be  used  is  now  ready,  the  starter  may 
be  added  to  it  in  about  the  proportion  of  ten  pounds  of  starter  to  one  hundred 
pounds  of  cream.  A  small  quantity  of  this  starter  is  saved  each  clay  and 
added  to  a  new  lot  of  pasteurized  skim  milk.  In  this  way  the  starter  is  car- 
ried on  from  day  to  day  and  a  new  lot  for  use  in  ripening  cream  is  prepared 
every  day. 

The  natural  starter  is  made  in  exactly  the  same  way  as  the  commercial 
starter,  except  that  in  place  of  the  ounce  of  pure  culture  which  is   bought 


*  See  page  190. 


MILK  PRODUCTS  6r 

from  a  dealer,  a  small  quantity  of  selected  sour  milk  is  added  to  the  pasteur- 
ized skim  milk.  The  starter  is  then  built  up  from  this  mixture  as  before 
described. 

This  in  general  is  an  outline  of  the  methods  used  for  making  cream 
ripening  starters.  The  successful  handling  of  starters  depends  entirely  on  the 
carefulness  with  which  the  skim  milk  is  pasteurized  and  the  skill  used  in  pro- 
tecting the  starter  from  outside  contamination  by  dust,  dirty  cans,  etc.  In 
some  cases  the  butter  maker  often  goes  so  far  as  to  wash  his  hands  before 
handling  his  starter.  These  refining  precautions  used  to  protect  the  pure  cul- 
ture and  the  starter  from  contamination  are  very  important. 

If  the  starter  does  not  give  satisfactory  results,  it  is  best  to  throw  it  away 
and  begin  a  new  one;  but,  when  once  obtained,  a  good  starter  should  be 
propagated  from  day  to  day  as  long  as  possible,  and  the  length  of  time  which 
it  may  be  kept  pure  depends  on  the  care  with  which  it  is  made  from  day  to 
day. 

It  is  always  better  to  seed  a  new  lot  of  pasteurized  skim  milk  with  a  por- 
tion of  fresh  starter  taken  out  just  before  it  is  poured  into  the  cream,  than  to. 
attempt  to  propagate  a  new  starter  every  day  by  means  of  buttermilk  ob- 
tained from  a  churning  of  cream  in  which  the  starter  was  used.  A  buttermilk 
starter  may  often  give  good  results;  but,  as  a  rule,  it  cannot  be  depended  on,, 
because  some  unpleasant  flavors  may  develop  in  the  cream  during  its  ripening. 
These,  of  course,  are  carried  into  the  buttermilk,  and  when  this  is  used  for- 
making  the  next  starter,  the  unpleasant  flavors  may  be  continued  in  the  butter 
from  day  to  day. 

One  of  the  important  elements  in  starter  making  is  the  ability  to  detect 
a  satisfactory  starter  when  it  is  made.  A  person  with  a  keen  sense  of  smell 
and  taste  is  able  by  inspection  to  select  a  good  starter  and  know  that  it  will 
produce  good  results,  while  other  persons,  without  this  ability,  are  unable  to 
accurately  judge  between  two  different  starters  and  they  may  keep  on  using  a 
poor  one  day  after  day  without  noticing  it.  This  faculty  of  judging  starters- 
may  be  cultivated  by  practice,  and  the  butter  maker  who  is  most  successful  in 
training  himself  to  detect  a  good  starter,  and  a  poor  one  as  well,  will  be  the 
most  successful  in  making  butter  of  a  fancy  grade. 

The  commercial  starters  are  more  expensive,  but  uniform, 
certain  and  convenient;  while  the  natural  starter  costs  little  or 
nothing  and  is  less  uniform  but  generally  successful.  Both  are  in 
common  use. 

Butter  made  from  ripened  cream,  besides  having  more  flavor, 
aroma  and  better  keeping  qualities,  is  more  readily  churned  and 
can  be  obtained  in  somewhat  larger  quantities  than  from  fresh 
cream.  Butter  made  from  fresh  cream  is  preferred  by  many  persons, 
and,  perhaps  it  may  be  said,  by  those  with  the  most  refined  taste. 
However,  the  market  for  such  butter  is  limited  and  it  must  be  sold 


62  CLEAN  MILK 

immediately  it  is  made.  Fresh  separated  cream  is  much  more 
readily  churned  than  gravity  cream. 

Cheese  is  made  from  the  curd  (casein  or  cheesy  portion)  of 
milk  obtained  by  souring  milk  or  by  curdling  it  with  rennet,  chiefly 
by  the  latter  method.  The  whey  is  removed  in  different  ways.  In 
soft  cheese,  as  Brie  or  Camembert,  the  whey  is  merely  permitted 
to  drain  naturally  from  the  curd.  The  whey  being  not  all  removed, 
soft  cheeses  keep  poorly. 

In  the  case  of  hard  cheeses,  the  curd  is  cut  up,  and  sometimes 
heated  to  no°  F.  to  toughen  it,  and  pressed  for  days.  Both  soft 
and  hard  cheeses  must  ripen,  which  process  takes  days  or  months. 
The  lactic  acid  germs  are  those  chiefly  instrumental  in  ripening 
hard  cheeses,  while  molds  and  miscellaneous  germs  ripen  the  soft 
cheeses.  In  ripening,  the  various  flavors  characteristic  of  the  special 
cheese  are  developed  through  the  action  of  chemical  products  formed 
by  the  growth  of  these  vegetable  parasites  or  germs.  In  addition, 
the  cheese  becomes  softened,  and  therefore  easier  of  digestion 
through  the  action  of  a  ferment  natural  to  milk,  resembling  rennet, 
the  latter  being  a  secretion  of  the  animal  stomach. 

How  important  is  the  influence  of  special  varieties  of  germs 
in  the  successful  making  of  cheese  may  be  appreciated  from  the  fact 
that  it  is  a  practice  to  smear  shelves  and  walls  of  new  factories  with 
fresh  cheese  (as  Brie  and  Limburger)  to  convey  to  them  the  special 
germs  necessary  to  produce  the  flavor  and  characteristics  of  the 
cheeses  which  it  is  desired  to  make.  A  starter  is  often  added  to 
milk  from  which  American  cheese  is  to  be  made.  As  in  the  case  of 
cream  for  butter,  the  addition  of  the  lactic  acid  germs  tends  to  crowd 
out  miscellaneous  and  undesirable  germs  and  give  a  more  certainly 
uniform  product.  The  commercial  starters  are  most  reliable  for  the 
ripening  of  cheese,  as  for  butter.  As  a  general  practice,  milk  can- 
not be  pasteurized  to  kill  the  undesirable  germs  before  adding  the 
starter,  when  cheese  is  to  be  made,  because  heating  the  milk  de- 
stroys the  ferment  in  it  which  assists  in  ripening  cheese,  and  heated 


MILK  PRODUCTS  63 

milk  does  not  curd  so  well  with  rennet.  Certain  of  the  sour  milk, 
and  of  the  soft  and  hard  cheeses  are,  however,  made  successfully 
from  pasteurized  milk  or  cream  to  which  is  added  a  starter. 

If  cheeses  made  from  unpasteurized  milk,  to  which  starters 
containing  lactic  acid  germs  have  been  added,  are  ripened  in  low- 
temperature  cellars,  the  miscellaneous  germs  are  not  likely  to 
develop. 

The  chemical  composition  of  buttermilk  and  whey,  bye-products 
in  the  manufacture  of  butter  and  cheese,  is  given  below. 

Buttermilk  is  usually  sour  from  lactic  acid,  while  the  proteids 
are  more  digestible  than  in  ordinary  milk  because  existing  in  a 
flaky  form.  Quite  recently  the  advantages  of  concentrated  and 
preserved  buttermilk  have  been  advocated.  Its  use  will  probably 
become  much  extended  in  time.  Also  an  innovation  is  buttermilk 
made  from  clean  skim  milk.  This  should  be  set  at  70°-8o°  F.  to 
clabber  when  it  is  churned  until  the  casein  is  in  a  finely  divided  state 
and  immediately  cooled  to  below  500  F.  and  sold  within  24  hours. 
A  pasteurized  skim  milk  may  be  used.*  There  is  a  great  field  for 
absolutely  clean  buttermilk  thus  made  for  consumption  in  cities. 

Whey  possesses  but  slight  food  value,  containing  only  the  ash, 
sugar  and  albumin  of  milk.  It  is  sometimes  the  only  food,  when 
combined  with  a  little  cream,  which  infants  with  delicate  digestion 
can  tolerate. 

We  also  append  a  table  showing  the  composition  of  butter. 

Buttermilk            Whey  Butter 

Per  Cent.  Per  Cent-  Per   Cent. 

Proteids     4.06                  0.81  1. 00 

Fat 0.93                 0.36  84.00 

Sugar  and  Ash  4.40                  5.71  300 

Good  cheese  contains  about  33  per  cent,  each  of  proteids  and 
fat,  and  possesses  two  to  three  times  the  food  value  of  meat,  pro- 
viding it  is  well  digested,  as  it  is  more  apt  to  be  if  cooked  with 
macaroni  or  vegetables. 

*  To  which  is  added  a  starter. 


64  CLEAN  MILK 

Skim  Milk 

Skim  milk  forms  a  valuable  food  for  man  or  beast,  especially- 
for  calves  and  pigs.  The  milk  should  be  fed  young  animals  sweet, 
and  warmed  to  the  temperature  of  the  body,  when  it  possesses 
about  one-half  the  value  of  whole  milk  for  food.  The  use  of  the 
hand  separator  at  the  farm  will  often  be  found  lucrative,  for  the 
reason  that  the  skim  milk  may  then  be  obtained  warm  and  fresh 
for  calves  or  pigs  and  the  cream  bring  as  large  a  price  as  the  whole 
milk,  while  retaining  the  most  valuable  element — the  nitrogen  in 
the  proteids  of  the  milk — on  the  farm.  This  because  the  nitrogen 
is  returned  to  the  soil  in  manure.  For  man,  skim  milk,  through  its 
proteids,  is  said  to  be  three  times  as  cheap  as  meat,  though  a  much 
more  bulky  food.  If  the  skim  milk  is  returned  from  the  creamery 
for  feeding,  it  is  best  that  it  be  first  pasteurized  to  kill  any  germs  of 
tuberculosis  which  may  be  contained  in  it  and  to  prevent  souring. 
Indeed,  when  skim  milk  is  to  be  fed  either  calves  or  pigs,  or  other 
animals,  it  is  best  to  previously  boil  the  milk  for  10  minutes  unless, 
the  cows  yielding  it  are  known  to  be  positively  free  from  tuber- 
culosis. Calves  should  be  permitted  to  suck  the  first  day  of  their 
existence,  and  then  may  be  given  whole  and  skimmed  milk  for 
ten  days,  gradually  reducing  the  whole  milk.  After  that  time 
they  may  be  given  only  skim  milk,  five  to  six  quarts  daily  in  three 
feedings  for  the  first  two  weeks.  At  the  end  of  this  time  five  pints 
of  skim  milk  may  be  fed  twice  daily  with  a  tablespoonful  of  flaxseed 
or  Indian  meal  to  supply  the  deficiency  of  fat  in  the  food.  A  liking- 
for  corn  meal  may  be  encouraged  by  placing  a  little  on  the  tongue 
after  feeding  milk.  Skim  milk  is  fed  pigs  in  the  proportion  of 
three  pounds  to  one  of  corn  meal ;  to  fowls,  also,  with  grain.  The 
utensils  and  troughs  in  which  the  skim  milk  is  fed  to  young - 
animals  should  be  kept  scrupulously  clean,  and  the  milk  should  not 
be  fed  sour.  Rich  milk  is  less  desirable  for  feeding  calves  or  pigs 
than  milk  comparatively  poor  in  fat  or  skim  milk.     Rich  milk  leads. 


MILK  PRODUCTS  65 

to  indigestion  and  diarrhea  and  not  infrequently  causes  the  death  of 
Jersey  calves  living  on  their  mother's  milk. 

Bye-Products 

In  speaking  of  milk  products  the  bye-products  of  milk  are 
used  to  an  extent  in  the  arts  but  little  appreciated.  This  has  re- 
cently been  brought  out  in  an  address  at  Chicago  by  Dr.  Nowak,  the 
inventor  of  a  process  for  using  skim  milk  in  the  tanning  of  leather. 
The  curd  or  casein  of  skim  milk  is  the  essential  part  of  the  milk 
employed  for  the  following  manufactures : 

For  sizing  straw  and  felt  hats;  for  making  and  glazing  paper; 
for  glazing  and  finishing  leather;  finishing  and  sizing  silk,  cotton, 
woolen  and  linen  goods;  for  making  wall  paper,  roofing  paper  and 
linoleum.  Also,  casein  is  an  important  ingredient  of  cements,  glues, 
putty,  woodfillers,  paints  (especially  dry  paints),  imitation  ivory  for 
balls,  and  buttons,  etc. 

Some  of  the  most  lasting  of  the  old  Roman  structures  were 
made  from  a  mixture  of  milk,  lime  and  sand,  and  the  most  cele- 
brated old  mural  decorations  of  Europe  from  casein  mixed  with. 
color. 


CHAPTER  IV 


FEEDING  FOR  MILK 


IN  feeding  cows  for  milk  the  most  essential  fact  to  grasp  is  that 
the  composition  of  milk  cannot  be  altered  to  any  extent  by  feed- 
ing. The  solids  may  be  increased  slightly  by  a  food  very  rich 
in  protein,  or,  on  the  other  hand,  the  solids  may  be  lessened,  if 
the  diet  is  very  watery,  but  the  percentage  of  fat,  sugar  and  pro- 
teids  in  the  milk  is  not  affected  to  any  degree  by  different  kinds  of 
foodstuffs.  One  often  reads  of  the  marked  influence  of  a  change 
of  food  in  increasing,  or  otherwise,  the  percentage  of  fat  in  the 
milk.  But,  while  a  sudden  change  in  the  ration  may  produce  a 
corresponding  alteration  in  the  percentage  of  fat  in  the  milk,  it  will 
be  found  only  a  temporary  matter.  The  single  exception  to  the 
rule  that  the  composition  of  milk  is  not  changed  by  feeding  is  when 
the  animals  are  not  in  a  normal  condition.  If  an  animal  has  not 
enough  food  to  be  maintained  in  a  normal  condition,  there  may  be 
a  disturbance  of  the  functions  of  the  udder,  as  of  any  other  function 
in  the  body,  and  therefore  alteration  in  the  composition  of  the  milk. 
The  theory  adopted  by  many  physiologists  teaches  that  milk 
is  formed  by  the  constant  breaking  down  of  the  substance  of  the 
cells  of  the  udder  into  the  proteids,  fat,  and  perhaps  to  some 
extent  the  sugar,  of  milk.  This  process  is  followed  by  a  rapid  re- 
building of  the  udder  cells.  But,  while  it  was  formerly  thought 
that  the  entire  udder  cells  were  being  continually  destroyed  in  the 


*  Consult  also  page  351  for  recent  advances  in  the  science  of  feeding  animals. 

66 


FEEDING  FOR  MILK  67 

making  of  milk,  it  now  appears  that  only  the  free  end  of  the  udder 
cell  is  broken  down.  The  contents  (protoplasm)  of  the  base  of 
each  cell,  together  with  the  cell  nucleus,  is  not  destroyed  but — after 
the  remaining  portion  of  the  cell  has  been  changed  into  milk 
constituents — the  cell  is  rebuilt.*  The  constituents  of  the  food  of 
cows  are  not  transformed  directly  into  milk,  but  are  altered  and 
absorbed  into  the  blood  and  serve  only  to  build  the  cells  of  the  udder, 
as  they  do  any  other  part  of  the  body. 

Moreover,  it  is  probable  that  the  content  of  the  udder  cells 
(protoplasm)  is  not  directly  changed  into  fat,-proteids,  and  milk 
sugar,  but  that  the  cells  manufacture  these  substances  out  of  the 
materials  brought  to  them  by  the  blood.f  There  are  perhaps  some 
136  million  fat  globules  formed  per  second  in  the  milch  cow's  udder, 
which,  it  is  estimated,  would  require  complete  renewal  of  the  en- 
tire secreting  tissue  of  the  udder  several  times  daily — if  the  udder 
cells  were  directly  transformed  into  fat.  Fat  in  the  milk  is  not  then 
due  to  a  breaking  down  or  fatty  degeneration  of  the  udder  cells,  but 
is  a  deposit  of  fat  in  the  cells  manufactured  from  the  blood  and 
lymph. 

No  one  of  the  separate  constituents  of  milk  is  directly  derived 
from  similar  constituents  of  food.  Fat  in  milk  is  not  derived 
directly  from  fat  in  food,  but  indirectly  is  formed  from  fat,  carbo- 
hydrates and  proteids  in  food.  Indirectly,  because  these  substances 
are  greatly  altered  before  and  after  they  reach  the  udder  in  the  blood. 

Therefore  an  excess  of  fat  in  the  food,  for  instance,  will  not 
increase  fat  in  the  milk.  The  kind  of  food  does  not  influence  the 
composition  of  milk  so  long  as  the  food  is  sufficient  in  amount  and 
properly  proportioned  or  "  balanced  "  in  its  constituents  to  fully 
nourish  and  sustain  the  animal. 

The  quality  or  composition  of  the  milk  from  any  cow  depends 
upon  the  natural  characteristics  of  the  cells  of  the  udder;  the 
quantity  of  milk  depends  on  the  capacity  for  rapid  cell-building 
and,  to  a  degree,  upon  the  size  of  the  udder.     But,  although  the 

*  This  destruction  is  probably  confined  to  but  a  few  of  the  udder  cells,  how- 
ever.    It  is  thought  that  globulin  is  thus  a  product  of  broken  down  cells. 

f  Fat,  casein  and  milk  sugar  are  the  results  of  glandular  activity  of  the  udder 
cells. 


68  CLEAN  MILK 

composition  of  milk  is  unaltered  by  food,  the  quantity  of  millc 
secreted  is  directly  dependent  upon  the  amount  and  kind  of  food. 
The  cells  of  the  udder  being  made  of  a  substance  similar  chemically 
to  the  proteids  of  the  milk,  there  must  be  an  abundance  of  protein 
in  the  food  to  constantly  rebuild  these  cells  as  they  liquefy  into 
milk.  Indeed,  the  proportion  of  protein  in  the  food  has  to  be  higher 
in  feeding  for  milk  than  for  any  other  purpose.  This  proportion 
has  been  determined  by  experience  and  experiments  (see  Wolff's 
table  below). 

While  it  is  possible  to  secure  the  proper  proportion  of  protein 
by  the  use  of  the  greatest  variety  of  fodders,  the  special  foodstuffs 
which  may  be  employed  in  any  given  case  should  be  determined 
chiefly  by  the  local  cost  of  special  fodders  and  the  price  of  milk. 

The  richer  a  food  in  protein  the  more  costly  is  it,  and,  if  the 
price  of  milk  is  low,  it  may  not  pay  to  increase  the  amount  of  pro- 
teids in  the  food  sufficiently  to  attain  to  the  maximum  milk-yield. 
A  food  rich  in  protein  tends  to  sustain  the  period  of  lactation  and 
keep  up  the  flow  of  milk — which  is  ordinarily  greatest  soon  after 
calving — for  a  considerable  period.  In  case  of  large  milkers  which 
receive  an  insufficient  supply  of  protein,  the  proteids  of  the  tissues 
of  the  body  are  called  upon  to  make  up -for  the  loss  of  protein  in  the 
formation  of  milk  from  the  udder  cells,  and  the  animal  rapidly 
loses  flesh. 

Notwithstanding  the  fact  that  the  composition  of  milk  cannot 
be  materially  altered  by  feeding  under  ordinary  circumstances,  yet 
by  good  feeding  and  breeding  (taking  advantage  of  increased  fat 
yield  in  milk  through  careful  selection),  it  has  been  found  possible 
in  several  generations  to  produce  an  animal  giving  milk  one  per 
cent,  richer  than  that  common  to  its  breed.  This  has  been  accom- 
plished by  some  in  the  case  of  the  Holsteins. 

Wolff's  original  feeding  standard  for  milk  cows,  per  day  and 
1,000  pounds  live  weight,  is  as  follows: 


FEEDING  FOR  MILK  69 

Pounds 

Digestible  protein  2.5 

"  fat    0.4 

"  carbohydrates    12.5 

Total  dry  matter  24. 

Nutritive    ratio     I    to    5.4 

The  nutritive  ratio  means  the  proportion  of  nitrogenous  to 
non-nitrogenous  constituents  of  the  food.  The  protein  represents 
the  nitrogenous,  and  the  fat  and  carbohydrates  together  represent 
the  non-nitrogenous  nutrients,  as  the  food  constituents  are  called. 
But  to  put  fat  on  the  same  basis  as  carbohydrates,  in  calculating  the 
nutritive  ratio,  the  percentage  of  digestible  fat  is  multiplied  by  2.25 
and  the  result  is  added  to  the  total  of  digestible  carbohydrates.  The 
reason  for  this  is  because  fat  is  thought  to  have  two  and  one-quarter 
times  the  food  value  of  carbohydrates,  since  a  given  weight  of  fat 
produces  two  and  one-quarter  times  as  much  heat  in  burning  as 
carbohydrates.  This  method  of  reasoning  is  realized,  however,  to 
be  very  imperfect.*  In  booksf  on  cattle  feeding  tables  showing  the 
composition  of  foodstuffs  may  be  found.  The  carbohydrates  are 
found  under  the  headings  Crude  Fibre  and  Nitrogen-Free  Extract. 
There  are  other  tables  showing  the  percentage  of  digestibility  of 
the  fat,  protein,  crude  fibre  and  nitrogen-free  extract  in  the  various 
fodders. 

By  multiplying  the  amount  of  any  of  these  constituents  in  any 
given  fodder  by  the  percentage  of  the  constituent  digestible,  we  get 
the  quantity  of  the  digestible  constituent  in  the  fodder.  Thus,  if  we 
look  at  a  table  showing  the  composition  of  hay:  Average  hay  we 
find  contains  in  the  100  lbs.  as  follows:  9  lbs.  protein,  2  lbs.  fat,  43 

*  The  exact  nutritive  value  of  fat  as  compared  with  carbohydrates  is  shown 
by  recent  experiments  to  be  as  follows: 

1  gram  of  carbohydrates  =  4180  calories. 
1  gram  of  fat  =  9400  calories. 

A  calorie  (small)  is  that  amount  of  heat  required  to  raise  1  gram  of  water  I  de- 
gree centigrade.  Therefore  the  heat  value  of  fat  is  about  2.25  times  that 
of  carbohydrates,  rather  than  2.5  times,  as  has  hitherto  been  accepted. 

f  Armsby's   "  Manual  of  Cattle   Feeding." 


yo  CLEAN  MILK 

lbs.  nitrogen-free  extract,  and  26  lbs.  crude  fibre.  To  find  the 
digestibility  of  these  nutrients  we  look  in  another  table  and  there 
discover  that  46  per  cent,  of  the  fat  in  hay  is  digestible,  57  per  cent, 
of  the  protein,  and  that  the  total  amount  of  nitrogen-free  extract  in 
a  coarse  fodder  represents  the  total  quantity  of  digestible  carbohy- 
drates it  contains.  So  in  our  100  lbs.  of  hay  we  calculate  that  there 
are  5.13  lbs.  of  digestible  protein  (multiply  9  X  -57);  and  0.92 
lbs.  of  fat  (multiply  2  X  46)  and  43  lbs.  of  carbohydrates 
digestible. 

When  we  cannot  figure  the  amount  of  nitrogen-free  extract  as 
equal  to  the  total  digestible  carbohydrates,  as  we  do  for  convenience 
in  a  coarse  fodder,  we  find  the  amounts  of  digestible  crude  fibre 
and  nitrogen-free  extract  in  the  tables  and  add  them  together  to- 
represent  the  total  digestible  carbohydrate  in  the  foodstuff.  Fat  is 
often  spoken  of  as  ether  extract  by  some  writers.  It  is  not  neces- 
sary, of  course,  to  try  to  secure  a  ration  which  shall  be  the  exact 
chemical  counterpart  of  Wolff's  table  above,  but  only  to  approach 
it  as  nearly  as  may  be,  especially  in  the  matter  of  protein.  The 
general  idea  should  be  to  take  the  foodstuffs  at  hand  and  look  up» 
the  amounts  of  digestible  nutrients*  they  contain  and  combine  them 
in  the  proper  proportions  as  indicated  by  Wolff's  table.  Protehrf- 
is  an  expensive  food  constituent  or  nutrient,  and  it  should  be  fed  in 
the  cheapest  form  of  fodder  available  in  the  locality.  The  best 
manner  of  feeding  is  to  weigh  out  the  food  necessary  for  the  whole 
number  of  cows  at  one  feeding  and  distribute  the  amount  to  each 
cow  in  proportion  to  her  weight,  secretion  of  milk,  etc.  Professor 
Haecker's  work  on  cattle  feeding  teaches  that  the  daily  quantity  of 
nutrients  should  be  proportioned  to  the  amount  and  richness  of 
daily  milk-yield  as  displayed  in  the  following  table.:}: 


*  Armsby's  "  Manual  of  Cattle  Feeding." 

t  In  cattle  foods  protein  costs,  by  weight,  twice  as  much  as  carbohydrates 
and  about  one-half  as  much  as  fat,  but  there  is  ordinarily  enough  fat  in  a 
ration. 

X  The  following  rations  were  selected  at  random  from  Hoard's  Dairyman. 


FEEDING  FOR  MILK  7i 

For  Cows  Weighing  1,000  Pounds. 


Milk-Yield 

Digest: 

ible  Nutrients  Re< 

luired 

A 

A 

f 

> 

r 

>\ 

Daily  Amount        Testing  in  Fat 

Protein 

Carbohydrates 

Fat 

lbs. 

Per    Cent. 

lbs. 

lbs. 

lbs. 

(3 

MO 

8.81 

•24 

10 

]4 

1. 17 

9.14 

.26 

(5 

I.24 

9-47 

.28 

(3 

I.50 

10.62 

■37 

20 

]4 

I.63 

11.28 

.42 

(5 

I.78 

11.94 

■47 

(3 

1.70 

H-54 

•45 

25 

J4 

I.87 

12-35 

•50 

(5 

i-95 

13-18 

.56 

}3 

i.qo 

12.43 

•5i 

30 

i4 

2.10   . 

13-42 

•58 

(s 

2.30 

14.41 

-65 

3 

2.10 

13-35 

■58 

35 

^4 

2-34 

14.49 

.66 

(5 

2.58 

I5-65 

•  74 

3 

2.30 

14.24 

.65 

40 

I4 

2-57 

I5-56 

-74 

(  5 

2.8s 

16.88 

•83 

,3 

2.70 

16.05 

.68 

50 

]* 

3-04 

17.70 

.90 

(  5 

339 

19-35 

1.01 

(3 

3-10 

17.86 

.92 

60 

J4 

3-5o 

19.84 

1.06 

(5 

3-92 

21.76 

1. 19 

^3 

3-5o 

19.67 

1.05 

70 

I4 

4.00 

21.98 

1.22 

(5 

4.46 

23.82 

1.36 

In  practice  it  may  also  be  broadly  stated  that  there  should  be  a 
certain  proportion  of  coarse  fodder,  or  roughage,  to  the  more  con- 
centrated foodstuffs,  as  grain  and  bye-products.  Haecker's  rule 
giving  one  pound  of  concentrated  food  for  every  three  pounds  of 
milk  yield,  affords  a  very  useful  basis  for  calculating  a  ration. 

Thus,  for  a  daily  ration,  20  to  40  lbs.  of  roughage,  including 
hay,  silage,  stover,  etc.,  may  be  fed  with  about  8  lbs.  of  concen- 
trates (consisting  preferably  of  a  mixture  of  a  variety  of  grains)  to 
a  cow  of  average  size  and  giving  about  25  lbs.  of  milk  daily.  To 
cows  giving  daily  35  lbs.  of  milk,  10  lbs.  of  concentrates  are  suitable, 


72  CLEAN  MILK 

and  if  the  milk  contains  5  per  cent,  of  fat,  12  lbs.  may  be  fed.  The 
great  milkers  are  often  fed  30  to  40  lbs.  of  roughage  with  15  to  16 
lbs.  of  a  grain  mixture  daily. 

Some  such  rations  as  the  following  may  be  used  for  milk  cows 
of  average  weight  and  giving  about  25  pounds  of  4  per  cent,  milk : 

Roughage,  20  lbs.  of  timothy  hay,  with  a  mixture  of  oats,  2 
lbs. ;  bran,  4  lbs. ;  and  gluten,  4  lbs.  This  contains  as  follows :  Dry 
matter,  26.3  lbs.;  digestible  nutrients — protein,  2.18  lbs.;  carbohy- 
drates, 13.09  lbs.;  fat.  0.58  lbs. 

Roughage,  20  lbs.  of  timothy  and  clover-hay,  with  a  mixture 
of  oats,  4  lbs. ;  barley,  3  lbs. ;  and  oil  meal,  1  lb.  This  is  equivalent 
to:  Dry  matter,  24.3  lbs.;  digestible  nutrients — protein,  1.88  lbs.; 
carbohydrates,  12. 1  lbs.;  fat,  0.6  lbs. 

Roughage,  30  lbs.  of  ensilage  and  10  lbs.  of  clover  hay,  with  a 
mixture  of  barley,  4  lbs.,  and  bran,  4  lbs.  This  ration  is  equivalent 
to:  Dry  matter,  25.5  lbs.;  digestible  nutrients — protein,  1.92  lbs.; 
carbohydrates,  11.92  lbs.;  fat,  0.56  lbs. 

Roughage,  ensilage,  30  lbs.,  and  oat  hay,  30  lbs.;  with  mixture 
of  ground  rye,  4  lbs.,  and  gluten  feed,  4  lbs.  This  feed  is  equivalent 
to:  Dry  matter,  23.56  lbs.;  digestible  nutrients — protein,  2.08  lbs.; 
carbohydrates,  13.32  lbs.;  fat,  0.54  lbs. 

It  will  be  seen  that  the  protein  is  a  little  low  in  all  these  ra- 
tions, according  to  Wolff's  standard  of  50  years  ago,  but  not  accord- 
ing to  the  Wisconsin  standard  of  Haecker. 

The  best  nutritive  ratio  for  milch  cows  is  still  a  matter  of 
dispute.  The  Wisconsin  standard  calls,  for  each  1,000  lbs.  of  live 
weight,  2.15  lbs  of  protein  and  sufficient  fat  and  carbohydrates  to 
give  a  nutritive  ratio  of  1  :  6.9.  The  Storrs  station  suggests  the 
same  amount  of  protein  as  Wolff  (2.5  lbs.),  but  an  increase  in  fat 
and  carbohydrates  enough  to  make  the  nutritive  ration  1  :  5.6. 

There  is,  however,  a  concensus  of  opinion  favoring  increasing 
the  proportion  of  protein  in  the  food  for  cows  having  large  milk 
yields.     Dr.  Lehmann's  standard  for  milch  cows  per  1,000  lbs.  live 


Protein. 

Fat. 

Pounds. 

Pounds. 

1.6 

0.3 

2.0 

•4 

2-5 

•5 

3-3 

.8 

Carbohy- 
drates. 
Pounds. 

Nutritive 
ratio. 

10 
11 

1:6.7 
1:6.0 

13 
13 

i:5.7 
i:45 

FEEDING  FOR  MILK  73 

weight,  with  different  milk  yields,  is  as  follows.     It  will  be  noted 
that  the  proportion  of  protein  is  higher  than  Haecker's  standards. 

Milk  per  cow 
per  day. 
Pounds. 
11 
16 
22 
27 

Cottonseed  (or  linseed)  meal  is  one  of  the  richest  foodstuffs 
in  protein  we  possess,  and  may  be  added  to  advantage  to  bring- 
up  the  proportion  of  protein  in  the  ration,  as  one  pound  of  the 
meal  is  equivalent  to  about  one-third  pound  of  digestible  protein. 
Xot  more  than  two  to  three  pounds  daily  of  cottonseed  meal  should 
be  fed,  however,  on  account  of  its  poor  digestibility  in  considerable 
amounts,  and  because  in  excess  it  may  render  milk  unfit  for  use  as 
an  infant,  food. 

The  following  mixtures  of  concentrates  may  be  employed  with 
an  appropriate  amount  of  roughage  (if  hay  is  used,  as  much  may 
"be  given  as  the  cow  will  eat  without  waste)  as  daily  rations  for  an 
average  cow : 

Bran,  4  lbs. ;  corn  chop,  3  lbs. ;  oil  meal,  1  lb.  Or,  2  parts  bran; 
2  parts  ground  oats;  2  parts  gluten,  and  1  part  oil  meal,  giving  8 
lbs.  of  the  mixture  daily.  Or,  4  lbs.  oats ;  3  lbs.  bran ;  1  lb.  oil 
meal.  Or,  4  lbs.  of  bran  and  4  lbs.  of  oats ;  or,  a  mixture  by  weight 
of  bran,  3  parts;  gluten  feed,  2  parts;  corn  chop,  2  parts;  and  oil 
meal,  1  part,  giving  8  to  10  lbs.  daily.  Professor  Haecker  estimates 
that  a  ration  containing  seven-tenths  of  a  pound  of  digestible  pro- 
tein, 7  lbs.  of  digestible  carbohydrates  and  one-tenth  of  a  pound  of 
digestible  ether  extract  (fat)  is  ample  for  the  physical  maintenance 
of  a  cow  weighing  1,000  lbs.,  not  giving  milk  or  subjected  to  other 
demands.  A  ration  having  the  proper  proportion  of  nitrogenous 
to  non-nitrogenous  nutrients,  or,  in  other  words,  the  proper  nutritive 
ratio,  according  to  Wolff,   is  now  called  a  balanced  ration.     Oil 


74  CLEAN  MILK 

meal  is  linseed  meal.  The  exact  amount  of  fat  in  the  daily  ration 
is  not  of  much  moment!  but  we  should  endeavor  to  approximate 
Wolff's  feeding  standard  with  the  more  recent  modification  of 
adjusting  the  ration  somewhat  to  the  quantity  and  richness  of 
the  milk-yield.  An  amount  of  salt  equal  to  one  teaspoonful  should 
be  given  with  the  feed  of  each  cow  twice  daily. 

Cows  may  be  watered  to  advantage  twice  daily ;  once  before 
they  are  turned  out  for  pasture  or  airing,  in  the  morning,  and  again 
before  the  evening  feeding.  The  best  method  is  to  always  have 
water  before  the  cows.  The  greater  amount  of  water  cows  drink, 
the  greater  their  milk-yield — within  certain  limits. 

The  matter  of  a  pure  water  supply  in  the  pasture,  farm  and 
•dairy  is  of  great  significance.  This  is  the  case,  not  because  the  milk 
is  contaminated  by  germs  or  poisons  swallowed  by  the  cow  in  im- 
pure water,  but  because  the  cow's  udders  become  contaminated  from 
wading  in  impure  water.  The  dairy  utensils  may  likewise  be  con- 
taminated by  washing  them  in  an  infected  water  supply  containing 
the  germs  of  typhoid  fever  or  dysentery.  The  presence  of  pools  of 
water  in  pastures  which  in  any  way  can  be  polluted  with  human 
excrement  or  urine  should  be  avoided.  Germs  or  micro-organisms 
existing  in  stagnant  pools  in  pastures  may  impart  a  fishy  taste  to 
milk  when  such  water  is  wallowed  in  or  swallowed  by  cows.  Water 
for  cattle  and  for  dairy  purposes  is  best  obtained  from  a  public 
water  supply  of  known  purity,  but  when  this  is  not  possible  a 
spring,  away  from  sources  of  pollution,  or  a  driven  well,  may  afford 
excellent  water.  Cows  do  not  like  very  cold  water.  Avoid  giving 
it  to  them  when  possible.  The  neighborhood  of  a  privy  or  manure 
pile  should  always  be  shunned,  and  surface  drainage  of  any  kind 
should  be  prevented  from  entering  the  well.  Below  the  depth  of 
three  and  one-half  feet  germs  do  not  live  in  the  soil.  Where  there 
is  any  doubt — and  some  doubt  must  always  exist  concerning  open 
wells  and  those  situated  near  dwellings — a  half  gallon  of  the  water 
should  be  submitted  to  a  competent  chemist  for  analysis.     Wells 


FEEDING  FOR  MILK  75 

must  be  free  of  all  solid  objects,  even  stones,  and  water  containing 
over  100  germs  to  the  cubic  centimeter  is  unfit  for  dairy  purposes. 

Sedgewick  states  that  if  more  than  100  germs  to  the  c.  c.  are 
present  in  water  it  should  be  regarded  as  suspicious;  and  if  there 
are  over  500  to  the  c.  c.  water  should  be  considered  polluted.  Wells 
should  not  be  nearer  than  50  feet  to  any  source  of  infection,  and 
should  be  walled,  surrounded  by  a  coping  and  covered.  Suspected 
water  should  be  boiled. 

If  springs  are  employed,  these  should  also  be  walled  about  and 
covered,  with  a  pipe  leading  the  water  for  use  from  the  spring.  No 
open  water  supply  is  permissible.  So  steps  leading  down  into  a 
spring  may  contaminate  the  water  by  the  feet  or  drainage  from  the 
surface.  Cisterns  may  be  used.  They  should  be  divided  by  a  porous 
brick  wall  so  that  the  water  will  filter  through  into  the  half  from 
which  the  supply  is  to  be  pumped.  An  arrangement  preventing  the 
water  first  flowing  from  a  roof  in  a  rain  from  entering  the  cistern 
should  be  made. 

The  kind  of  food  and  manner  of  feeding  cows  has  an  influence 
upon  milk  which  is  of  much  importance,  especially  when  the  milk  is 
to  be  used  by  infants. 

Many  chemical  substances  in  the  food  are  eliminated — either 
changed  or  unchanged — in  the  milk,  and  may  impart  to  it  an 
unnatural  odor,  taste  or  appearance,  and  may  render  it  unfit  for 
food.  A  sudden  change  from  dry  fodder  to  grass,  or  any  other 
green  food  in  considerable  amount,  is  apt  to  give  rise  to  milk  which 
will  cause  digestive  troubles  in  babies. 

Fresh  corn  fodder  in  considerable  quantity,  when  fed  to  cows, 
will  often  render  the  milk  harmful  to  infants.  While  roots  and 
ensilage  are  commonly  said  to  produce  a  milk  which  will  disagree 
with  infants,  yet  I  believe  these  are  harmless  when  fed  in  moderate 
quantities  and  after  milking. 

Silage  should  not  be  given  in  a  greater  amount  than  twenty 
pounds  daily,  and  not  more  than  two  pounds  of  oil  meal  should  be 


j6  CLEAN  MILK 

fed,  when  the  milk  is  especially  intended  for  infants'  use.  The  feed- 
ing of  spoiled,  moldy  ensilage,  and  remnants  of  ensilage  which  have 
•been  allowed  to  accumulate  about  the  barn,  are  chiefly  responsible 
for  the  harm  this  foodstuff  inflicts  upon  milk.  In  fact,  some 
authorities  say  that  a  ration  of  under  40  lbs.  daily  per  cow  is  not 
damaging  to  milk.  Some  of  the  largest  buyers  of  milk  in  the  United 
States,  however,  refuse  milk  from  ensilage-fed  cows,  and  those 
versed  in  the  use  of  milk  for  baby  feeding  find  that  a  small  feed  of 
ensilage  is  safer.  The  only  real  objection  to  silage  feeding  lies  in 
the  use  of  sour  and  moldy  ensilage  and  in  feeding  such  large 
amounts  that  the  cows  have  diarrhea.  In  the  latter  case  it  is  impos- 
sible to  keep  either  cows  or  premises  clean.  Any  sloppy  or  green 
fodder  which  produces  diarrhea  is  therefore  to  be  avoided.  "When 
certified  milk  is  produced  there  should  never  be  any  sudden  change 
in  the  ration,  as  the  composition  of  the  milk  may  be  thus  suddenly 
altered.  When  the  feeding  of  ensilage  is  begun  in  the  autumn 
very  small  quantities  must  be  given  at  first  and  the  quantity  should 
only  be  gradually  increased — if  the  milk  is  intended  for  infants' 
food.  Otherwise  the  milk  will  be  likely  to  cause  vomiting  and  diar- 
rhea in  babies.  The  same  remark  applies  to  the  use  of  corn  stalks 
in  summer.  They  should  not  be  fed  to  cows  until  after  the  corn  is 
in  blossom  and  then  only  in  small  quantities  at  the  beginning. 
Grass,  hay,  clover  and  grains  have  been  considered  the  best  food 
for  cows  supplying  milk  for  use  by  babies,  but  a  moderate  ration 
of  silage  is  allowable.  The  melting  point  of  butter  may  differ  ac- 
cording to  the  feed  of  the  cows.  Gluten  products  and  gluten  meal 
tend  to  produce  a  soft  butter,  while  cotton  seed  meal  tends  to  make 
a  hard  butter.  Barley  and  peas  in  grain  mixtures  give  rise  to  a 
softer  butter  than  cornmeal  or  wheat  bran  with  cotton  and  linseed 
meal. 

The  time  of  feeding  is  a  matter  of  great  moment.  In  general, 
it  may  be  said  that  milk  cows  should  only  be  fed  after  milking  to 
avoid  dust  in  the  barn,  and  fodder,  when  given  at  this  time — as 


FEEDING  FOR  MILK  j? 

mangolds,  turnips,  rutabagas,  carrots  or  their  tops — will  not  im- 
part a  bad  odor  or  taste  to  the  milk.  Turnips,  turnip  tops  and  ruta- 
bagas are  excluded  from  the  ration  by  some  milk  buyers.  A 
turnip  taste,  however,  is  frequently  due  to  germ  contamination. 
It  is  not  necessary  to  feed  cows  in  order  that  they  be  quiet  during 
milking;  they  can  soon  be  habituated  to  being  fed  after  milking. 
Indeed,  so  great  is  the  danger  of  disseminating  germs  in  the  air 
when  cows  are  fed  before  or  during  milking,  that  it  is  now  recog- 
nized that  when  dry  fodder  is  thus  fed  it  is  impossible  to  secure- 
clean  milk.  Moreover,  when  hay  is  kept  in  mows  open  to  the  cow- 
barn,  it  is  very  difficult  to  produce  clean  milk.  If  feeding  is  done 
at  milking  time,  it  should  only  be  moistened  grain. 

Of  26  samples  of  hay  examined  at  the  Storrs  Experiment 
Station,  it  was  found  that  on  the  average  a  gram  (quarter  tea- 
spoonful)  contained  16,800,000  bacteria.  Seventy-two  per  cent,  of 
these  were  liquefiers  and  ten  per  cent,  were  spore-forming  bacteria.. 
The  latter  cannot  be  killed  by  boiling  in  the  spore-forming  stage  and 
therefore  exist  in  pasteurized  milk  and  lead  to  its  decomposition. 

The  liquefiers  cause  digestion  of  the  milk  and  destroy  the 
casein.  The  varieties  of  bacteria  in  hay,  which  are  very  numerous, 
diminish  with  storing;  the  miscellaneous  acid  bacteria  double  with 
storing  in  the  barn,  but  the  liquefiers  diminish  one-third.  Hay 
dust  is  one  of  the  chief  sources  of  germ  contamination  of  milk. 
True  lactic  acid  bacteria  are  not  found  in  hay  and  therefore  it  is. 
riot  the  source  of  them  in  milk.  Hay  should  be  moistened  before 
it  is  fed. 

There  are  certain  pasture  plants  which  are  harmful  to  milkr. 
and  sometimes  to  human  consumers  of  it.  Among  these  are  the 
following:  Poison  ivy,  lupines,  wormwood,  poison  oak,  meadow 
saffron,  Jamestown  weed,  sorrel,  poisonous  mushrooms,  wild  mus- 
tard, carrot  tops,  milkweed,  sumach,  henbane  and  skunk  cabbage- 


Bull.  51  Storrs  Agric.  Exper.  Sta.  1908. 


;8  CLEAN  MILK 

The  disease  known  as  milk  sickness,  or  trembles,  which  sometimes 
attacks  man,  has  been  attributed  to  the  drinking  of  milk  from  cows 
feeding  on  poison  ivy,  mushrooms,  etc.  It  is  now  known  that 
trembles  is  probably  caused  by  a  special  germ  (B.  lactimorbi),  as  it 
may  be  reproduced  indefinitely  by  feeding  the  flesh  of  diseased  to 
healthy  animals.  Night  exposure  is  most  dangerous  to  animals — 
perhaps  because  the  germ  is  introduced  by  a  biting  insect.  Cows 
usually  do  not  sicken  with  trembles  while  they  are  regularly  milked, 
although,  without  seeming  sick,  such  infected  animals  may  be  capa- 
ble of  giving  the  disease  to  man  drinking  their  milk.  If  milking  is 
stopped  the  cow  may  suddenly  sicken.  Cattle  with  trembles  show 
dulness  and  weakness,  and  tremble,  pant,  and  run  against  objects. 
Fever  is  absent.  The  bowels  are  constipated  but  sometimes  loose 
with  discharge  of  blood  and  mucus.  The  animal  lies  with  the 
head  to  one  side  and  the  breath  is  strong  with  acetone.  Animals 
finally  lie  quivering  and  may  be  unable  to  rise.  The  disease  is  quite 
fatal  in  man  and  animals.  From  three  to  six  days  after  drinking 
milk  from  cows  affected  with  the  disease,  symptoms  appear  in  man. 
It  begins  with  malaise,  vomiting,  constipation,  pain  in  the  belly,  ace- 
tone breath  and  thirst.  Twitching  of  the  muscles,  weakness  and 
paralysis,  with  difficulty  in  breathing,  may  occur.  About  half  the 
cases  die.  The  disease  lasts  about  a  week  or  ten  days.  It  is  only 
known  in  the  United  States — especially  in  newly  settled  parts  of 
the  Southern  and  Middle  States.  Meadow  saffron  consumed  by- 
cows  may  lead  to  severe  diarrhea  in  man  drinking  their  milk. 

Milk  is  not  of  good  quality  for  any  purpose  when  the  animals 
yielding  it  are  fed  upon  swill,  brewers'  grains  or  food  in  a  state  of 
marked  fermentation  or  putrefaction.  Such  milk  may  cause  digest- 
ive disturbances  in  man — particularly  in  babies — and  the  manure 
is  very  soft  and  stinking  from  cows  eating  fermented  food,  and 
splashes  about,  and  is  therefore  more  apt  to  soil  the  cow  and  milk. 
The  milk  produced  with  brewers'  grains  does  not  keep  sweet  so 
long  as  good  milk  should,  neither  are  the  cows  consuming  large 


FEEDING  FOR  MILK 


79 


quantities  of  it  long-lived.  The  use  of  this  food  is  now  prohibited 
by  law  in  most  cities.  Dried  brewers'  and  distillers'  grains  consti- 
tute wholesome  food  for  cows.  Moldy  hay,  straw  or  grain ;  decayed 
leaves,  salt  hay,  onions,  garlic  and  cabbage  may  give  to  milk  a  bad 
odor  or  flavor. 

The  expressed  pulp  from  the  sugar  beet  is  inadvisable  as  a  food 
for  cows,  because  of  its  richness  in  potassium  salts,  which  find  their 
way  into  the  milk  and  render  it  unfit  food  for  human  beings  or 
animals. 

The  milk  of  cows  receiving  drugs  is  unsuitable  for  food,  since 
many  medicines  are  eliminated  in  the  milk.  Furthermore,  the  milk 
of  cows  sick  in  any  manner  should  be  withheld  from  feeding  pur- 
poses, as  poisons  in  the  blood  or  germs  of  disease  may  be  conveyed 
to  man  or  animals  in  the  milk  from  the  sick  cow.  The  milk  of 
cows  undergoing  the  tuberculin  test  may  be  used  as  food  unless 
the  animal  reacts  to  the  test,  when  it  should  be  permanently  rejected 
for  human  consumption,  or  boiled  before  feeding  it  to  animals. 


CHAPTER  V 


HOUSING  AND  CARE  OF  COWS 


IN  considering  the  practical  details  concerned  with  the  housing 
and  care  of  cows,  and  the  handling  and  marketing  of  milk, 

our  object  will  be  to  emphasize  the  essentials  required   for 

the  production  of  clean  milk. 

Many  different  methods  may  be  employed  to  attain  the  same 
end,  but  certain  principles  are  essential.  Ideal  methods  are  un- 
fortunately expensive,  and  the  most  approved  appointments  of  the 
modern  stable  and  dairy  rival  those  of  the  surgeon's  operating 
room  in  elaborateness  and  cost.  Nevertheless,  milk  which  will 
fulfil  all  the  requirements  necessary  for  "  certification  "  can  be 
produced  by  care  and  cleanliness  in  an  ordinary  stable,  and  without 
any  great  outlay  for  plant. 

The  Barn 

The  essentials  are  that  it  shall  be  clean,  light,  airy,  free  from 
dust,  flies  and  odors.  In  regard  to  the  air  space  in  a  barn,  this  is 
a  matter  which  depends  wholly  on  the  ventilation.  When  the 
ventilation  is  good,  500  cubic  feet  of  air  per  cow  is  sufficient,  as 
the  air  is  in  constant  movement.  The  number  of  cubic  feet  of  air, 
rather  than  air  space,  is  the  important  matter.  The  King  system 
for  stables  is  that  commonly  used,  the  principle  being  to  secure  a 
current  of  air  traveling  at  the  rate  of  200  to  500  cubic  feet  per 
minute  through  the  barn. 

The  animal's  heat  is  used  to  aid  the  movement  of  air.  If  the 
stable  is  too  high,  the  animal-heat  will  be  lost,  so  that  in  cold 
climates  a  height  of  8  feet  is  sufficient,  while  a  good  width  for  a 

80 


HOUSING  AND  CARE  OF  COWS  81 

stable  is  36  feet.  The  cows  are  to  be  placed  in  two  rows  running 
the  length  of  the  stable,  and  either  facing  each'  other  or  toward 
the  outside  of  the  building.  There  is  much  disagreement  as  to 
-which  arrangement  is  the  better.  If  the  cows  face  outward,  there 
should  be  feeding  alleys  in  front  of  them  at  least  6  feet  wide,  while 
the  central  aisle  in  the  barn  behind  them  is  used  for  removing  man- 
ure. If  the  cows  face  inward,  the  central  aisle  between  the  rows 
of  cows  is  used  for  feeding  purposes.  In  either  case  an  overhead 
railway  is  often  used  for  removing  manure  from  the  centre  aisle, 
when  the  cattle  face  outward,  or  for  carrying  feed  when  the  ani- 
mals face  toward  each  other.  The  writer  gives  the  preference  to 
the  plan  of  facing  the  cows  towards  the  outside  of  the  building. 
By  this  arrangement  the  cows  get  more  air  and  light,  and  their 
breath  does  not  commingle.  At  the  same  time  the  manure  can 
be  more  readily  removed,  which  is  more  important  than  ease  of 
feeding,  for  the  production  of  clean  milk.  In  the  cow  stall,  the 
chief  object  should  be  to  have  an  arrangement  which  keeps  the 
cows  wholly  apart  and  does  not  cumber  the  floor  so  as  to  make 
places  where  dirt  can  collect.  The  best  floors  are  of  concrete,  cov- 
ered with  cement,  and  made  somewhat  rough,  so  that  the  cattle 
will  not  slip.  Competent  dairy  men  place  layers  of  tar  paper  under 
the  upper  layer  of  cement,*  or  cover  the  cement  with  movable  wood 
flooring,  under  the  cows,  to  prevent  them  from  lying  on  this  hard 
and  cold  substance.  (See  Appendix.)  If  not  of  cement,  the  floor 
should  be  of  planed,  matched  planking,  and  the  cracks  filled  in  with 
tar.  In  case  planking  is  used,  it  is  best  at  any  rate  to  have  the 
gutters  of  cement. 

To  secure  drainage  of  the  floor  of  the  stall,  the  rear  half  of 
it — that  is,  the  half  nearest  the  manure  trench — should  have  a  fall 
of  two  inches.     The  manure  trench  should  be  sixteen  inches  wide 


*  On  top  of  three  inches  of  concrete,  place  three  layers  of  building  paper.  Coat 
the  two  lower  layers  of  paper  with  melted  tar.  Add  three  inches  of  concrete 
above  the  paper. 


S2  CLEAX  MILK 

and  about  eight  inches  deep.  The  trench  should  have  a  fall  for 
drainage,  being,  for  instance,  six  inches  deep  at  one  end  and  ten 
inches  deep  at  the  other;  or  the  whole  floor  of  the  stable  may  be 
made  to  slope,  with  the  trench  of  the  same  depth  from  end  to  end. 

Special  milking  barns  (used  only  for  milking)  are  not  at  all 
necessary  to  produce  clean  milk,  since  bacteria  are  as  few  in  milk 
withdrawn  in  ordinary  clean  barns  as  in  milk  withdrawn  in  barns 
used  only  for  milking  purposes. 

Stables  should  be  cleaned  by  daily  scrubbing  with  a  washing 
compound  followed  by  the  use  of  the  hose. 

A  number  greater  than  forty  cows  is  not  desirable  in  one 
barn.  There  should  be  a  continuous  window  space  along  each 
side  of  the  barn.  The  windows  may  hinge  from  below,  or  be  made 
to  open  and  close  as  one,  by  means  of  a  continuous  rod.  In  cold 
climates,  the  sides  of  the  barn  may  be  built  of  two  layers  of  inch, 
matched  boards  with  a  space  of  eight  inches  between,  filled  in  with 
cut  straw  or  sawdust.  Besides  this,  building  paper  should  be  laid 
inside  each  layer  of  the  boarding.  The  inner  layer  of  boarding 
should  be  without  beading  and  laid  perpendicularly.  The  ceiling 
overhead  should  be  perfectly  tight.  If  it  is  composed  of  a  double 
floor  with  building  paper  between,  there  is  no  reason  why  hay 
should  not  be  kept  overhead,  providing  it  is  brought  down  into  a 
room  separate  from  the  main  stable.  There  should  be  tightly-fitting 
double  windows  in  winter  in  cold  climates.  The  King  ventilating 
system  consists  of  numerous  flues  on  all  four  sides  of  the  building 
for  the  intake  of  air,  4x4  inches  in  diameter,  and  opening  three 
or  four  feet  below  the  ceiling  outside  the  stable,  and  entering  the 
stable  just  under  the  ceiling.  These  are  furnished  with  sliding 
doors,  or  closed  with  an  arrangement  like  a  furnace  register  in  a 
dwelling  house.  The  out-take  for  air  should  be  only  one  for  every 
twenty  cows  or  less,  being  a  shaft  with  openings — the  same  size 
as  the  shaft  one  foot  above  the  floor  and  just  below  the  ceiling. 
This  shaft  should  be  placed  on  the  outside  of  the  centre  of  one  side 


HOUSING  AND  CARE  OF  COWS  83 

of  the  barn,  and  should  be  carried  straight  upward  like  a  chimney, 
six  feet  higher  than  the  top  of  the  roof. 

The  shaft  or  flue  should  be  absolutely  air-tight,  and  may  be 
made  of  metal,  covered  with  building  paper,  or  preferably  of  two 
layers  of  wood,  with  filling  of  sawdust  or  building  paper  between, 
■and  covered  with  a  cap,  to  keep  the  rain  out,  one  foot  above  the  top. 
The  openings  near  the  floor  and  at  the  ceiling  should  be  provided 
with  doors  or  dampers  of  some  kind.  The  number  of  flues  and  size 
of  flues  are  governed  by  the  number  of  cows  in  the  barn.  Only 
one  flue  is  necessary  for  the  out-take  of  air  when  there  are  less 
than  thirty  cows  in  the  barn. 

1  flue  1  ft.  square  for  6  cows. 

i     "  1x2"        "  "  10       " 

1  "  2x2    "        "  "  20       " 

2  "  2x2"        "  "  40       " 

3  "  2x2    "        "  "  100       " 

The  movement  of  air  in  the  ventilating  system  is  brought 
about  by  the  following  forces :  Wind  pressure  against  the  barn, 
forcing  air  into  the  building;  wind  suction  on  leeward  side,  tending; 
to  suck  air  out ;  wind  blowing  across  top  of  ventilating  shaft,  tend- 
ing to  suck  air  out  of  it ;  by  difference  of  temperature  between  the 
air  inside  and  that  outside  the  building.  Thus  air  enters  the  intake 
near  the  ceiling  and  is  distributed  over  the  building.  The  air  at 
the  bottom  of  the  barn  is  the  coldest.  In  cold  weather  the  bottom 
opening  of  the  out-take  shaft  should  be  open,  and  the  upper  opening- 
near  the  ceiling  shut.  The  cold  air  is  then  sucked  from  the 
floor  of  the  barn  up  the  flue  into  the  outer  air.  In  hot  weather 
the  upper  opening  in  the  out-take  flue  may  be  opened,  and  the 
lower  closed.  This  permits  of  escape  of  heated  air  from  the  stable, 
and  may  be  done  at  any  time  to  secure  better  ventilation,  but  at 
the  expense  of  the  animal  heat.  In  order  that  the  system  work 
well,  it  is  essential  that  every  part  of  the  barn  be  absolutely  tight, 
with  well-insulated  walls  to  prevent  chilling  and  condensation  of 
moisture,  as  about  ten  pounds  of  water  are  eliminated  daily  from 


84  CLEAN  MILK 

the  lungs  and  skin  of  a  cow.  The  doors  leading  outdoors  should, 
be  double.  There  must  be  no  leakage  of  air  in  or  out  anywhere, 
except  through  the  ventilating  system — even  hay  chutes  must  be- 
closed,  and  no  escape  of  air  into  the  loft  be  permitted.  It  is  not 
possible  to  state  just  how  many  intake  flues  there  should  be,  but 
it  is  better  to  have  them  numerous  on  each  side  of  the  barn  (6  feet 
apart),  as  they  can  easily  be  closed  if  necessary. 

It  is  feasible  to  sustain  a  pretty  even  temperature  in  a  tightly 
built  stable  properly  ventilated — somewhere  between  55 °  and  6o°  F. 
in  cold  weather.  If  the  air  is  too  hot,  the  out-take  flues  are  not 
sufficient;  if  too  much  cold  air  rushes  in,  the  intakes  should  be  closed 
to  some  extent,  as  there  should  be  no  considerable  drafts  when  the 
system  is  working  properly.  The  intake  flues  are  commonly  built 
in  the  walls  of  the  barn,  and  the  out-take  flues  may  also  be  so  con- 
structed, in  which  case  they  are  made  of  two  layers  of  tight  board- 
ing with  roofing  paper  between. 

Metal  flues  are  not  so  advisable  in  cold  climates  as  wooden 
ones,  because  moisture  condenses  more  readily  in  them.  The  fol- 
lowing sketches  of  some  barns  ventilated  by  the  King  system  are 
taken  from  King's  "  Physics  of  Agriculture,"  to  which  the  author 
wishes  to  acknowledge  his  indebtedness  for  some  of  the  matter  con- 
cerning ventilation  presented  above.  Old  stables  can  be  remodeled 
with  concrete  floors,  and  later  the  ventilating  system,  with  stuffed 
walls  and  tight  ceilings,  doors  and  windows,  may  be  added. 

Sketch  A  shows  two  methods  of  ventilating  a  dairy  barn.  On 
the  right  (Fig.  1)  the  ventilating  flue  D  F  rises  straight  from  the 
floor,  passing  out  through  the  roof  and  rising  above  the  ridge. 
One,  two  or  three  of  these  would  be  used  according  to  number  of 
cattle.  The  flues  should  be  at  one  or  the  other  side  of  the  cupola 
rather  than  behind  it.  On  the  left  C  E  represents  how  a  hay  chute 
may  be  used  also  for  ventilating  flue.  In  each  of  these  cases  the 
ventilating  flue  would  take  the  place  of  one  cow.  This  method 
would  give  the  best  ventilation,  but  has  the  objection  of  occupying^ 


HOUSING  AND  CARE  OF  COWS 


85 


^valuable  space.  C,  in  the  feed  chute,  is  a  door  which  swings  out 
when  hay  is  being  thrown  down,  but  is  closed  when  used  as  a 
ventilator,  the  door  not  reaching  quite  to  the  floor.  To  take  air  into- 
this  stable,  if  it  is  built  of  wood  with  studding,  openings  would 


Fig.  1. 


Sketch  A — Two  methods  of  ventilating  a  dairy  barn. 


be  left  at  A  about  4x12  inches  every  twelve  or  sixteen  feet,  and  the 
air  would  enter  and  rise  between  the  sheathing  of  the  inside  and  the 
siding  on  the  outside,  entering  at  B  as  represented  by  the  arrows. 
Pig-.  2  shows  intakes  through  a  brick  wall. 


86 


CLEAN  MILK 


Sketch  B  shows  a  method  of  ventilating  a  lean-to  stable.  The 
air  enters  as  represented  by  the  arrows  at  A  B  and  passes  out 
through  a  flue  built  on  the  inside  of  the  upright  or  main  barn. 
This  flue  may  rise  directly  through  the  roof  or  it  may  end  at  E 
as  shown  in  the  figure,  the  air  passing  through  a  cupola.  If  the 
upright  barn  has  a  balloon  frame,  then  the  space  between  the 
studding  could  be  used  as  ventilating  flues.  These  flues  could  be 
made  tighter  by  covering  inside  and  out  on  the  studding  with  the 
lightest  galvanized  iron. 


Sketch  B — Method  of  ventilating  a  lean-to  stable. 


Sketch  C  shows  a  section  of  the  cow  stable  of  the  dairy  barn  at 
the  Wisconsin  Experiment  Station.  A  single  ventilating  flue  D  E 
rises  above  the  roof  of  the  main  barn,  and  is  divided  below  the 
roof  into  two  arms  A  B  D,  which  terminate  at  or  near  the  level 
of  the  stable  floor  at  A  A.  These  openings  are  provided  with  ordi- 
nary registers,  with  valves  to  be  opened  and  closed  when  desired. 
Two  other  ventilators  are  placed  at  B  B,  to  be  used  when  the  stable 
is  too  warm,  but  are  provided  with  valves  to  be  closed  at  other  times. 
C  is  a  direct  12-inch  ventilator  leading  into  the  main  shaft,  and 
opening  from  the  ceiling,  so  as  to  admit  a  current  of  warm  air  at 


HOUSING  AND  CARE  OF  COWS 


87 


all  times  to  the  main  shaft  to  help  force  the  draft.  This  ventilat- 
ing shaft  is  made  of  galvanized  iron,  the  upper  portion  being  3 
feet  in  diameter.  The  covering  on  the  outside  is  simply  for  archi- 
tectural effect.    G  F  show  method  of  intake  of  air. 


Sketch  C — Section  of  the  cow  stable  of  the  dairy  barn  at  the  Wisconsin 
Experiment  Station. 


In  mild  climates  a  single  storied,  high  studded  (10  to  12  ft.) 
barn  may  be  best,  without  the  King  system  of  ventilation  but  with 
a  monitor  roof.  This  resembles  a  small  second  story  running  along 
the  top  of  the  main  roof  and  having  numerous  windows  in  its  side 
and  ventilators  on  its  top — both  to  aid  ventilation. 


88  CLEAN  MILK 

The  Cloth  Method  of  Stable  Ventilation 

Quite  recently  there  has  come  into  existence  a*  new  system  of 
ventilating-  barns  by  means  of  windows  covered  with  cheap  cotton 
cloth.  No  method  could  be  simpler  or  less  expensive  and  the  results 
thus  far  reported  have  been  very  favorable. 

Thus  Ellis  M.  Santee.  of  the  Dairy  Department  of  U.  S. 
Bureau  of  Animal  Industry.  Washington.  D.  C,  writing  in  Hoard's 
Dairyman  of  May  17th,  1907,  records  some  conclusions  from  ex- 
haustive experiments  with  cloth  ventilation  as  compared  with  the 
King  system.  He  affirms  that  even  with  the  thermometer  register- 
ing 43  degrees  below  zero,  water  never  froze  in  the  barn  with 
cloth-covered  windows.  Also  that  the  difference  in  temperature  in 
barns  with  cloth-covered  windows  and  in  those  with  all  glass  win- 
dows was  but  1  to  3  degrees.  Moreover,  in  the  stables  ventilated 
with  cloth-covered  windows,  the  humidity  was  7  to  10  per  cent. 
lower  than  in  the  barns  ventilated  by  the  King  system.  Finally  he 
records  the  fact  that  many  good  dairymen  have  closed  the  outlets 
and  inlets  of  their  King  system  to  give  place  to  the  cloth  curtain 
method.  Glass  windows  to  secure  proper  sunlight  (Santee)  should 
be  alternated  with  cloth-covered  openings,  the  proportion  being  3 
sq.  ft.  of  glass  and  2  sq.  ft.  of  cloth-covered  openings  for  each 
1,000  lbs.  of  animal.  The  cloth  should  be  muslin  of  the  first  grade 
better  than  cheesecloth,  costing  5  to  6  cents  per  yard. 

Some  farmers  are  supplementing  the  King  system  of  ventila- 
tion with  the  cloth  method.  This  is  superfluous  if  the  King  system 
has  been  properly  installed.  With  the  chimney  flue  in  the  King 
system,  for  creating  a  draft,  there  is  good  ventilation  with  little 
air  moving  along  the  ground  and  heat  is  not  wasted  in  high  winds. 
This  is  not  the  case  with  cloth  ventilation.  Moreover,  if  the  cloth 
becomes  wet  and  freezes,  ventilation  may  be  nil  for  the  time. 

Cheesecloth  is  now  often  used  in  place  of  muslin  and  over 
all  the  windows  of  the  barn.  If  fastened  outside  the  windows  the 
glass  may  be  closed  when  it  is  so  desired. 


HOUSING  AND  CARE  OF  COJVS  89 

In  summer,  mosquito  netting — with  larger  meshes — will  give 
better  ventilation. 

Some  farmers  are  using  cheesecloth  the  year  round  on  their 
barns  on  all  windows — having  discarded  glass  altogether — and,  it 
is  said,  with  good  results,  even  in  very  cold  weather.  The  cheese- 
cloth ventilation  certainly  proves  satisfactory  in  comparatively  mild 
climates  (as  the  Pacific  coast)  and  is  at  once  so  simple  and  cheap 
that  it  may  here  well  supplant  the  King  system  and  is  worthy  of 
trial  in  colder  climates  in  barns  lacking  other  or  satisfactory  forms 
of  ventilating  systems. 

The  last  word  has  not  been  said  on  stable  ventilation  by  a  great 
deal.  Ventilation  is  a  very  complex  and  difficult  problem  unless  one 
can  produce  a'  forced  draught  of  warm  or  cold  air  by  blowers,  as 
is  now  done  in  large  public  buildings.  It  has  been  taught  that  the 
impure  air  (C02)  falls  to  the  floor  in  stables  and  is  thus  removed 
by  the  King  system.  This  is  not  entirely  true,  as  there  are  all  sorts 
of  currents  and  counter  currents  in  barns. 

One  fact  is  certain,  warm  air  rises.  In  the  dwelling-house 
warm,  fresh  furnace-heated  air  rises  and  the  air  containing  most 
COo  falls  to  the  floor.  In  the  stable  the  warm  air  is  furnished  by 
animal  heat  and  the  animal  emanations  must  rise  to  some  extent 
with  the  warmed  air. 

If  there  is  only  a  ventilator  on  the  roof  this  may  allow  some 
warm,  vitiated  air  to  escape,  but  then  the  current  may  be  reversed 
by  wind  pressure  and  cold  air  descend.  A  simple  way  of  securing 
a  constant  circulation  of  air  is  the  Rutherford  method,  which  has 
been  in  use  for  14  years  and  is  installed  in  the  Dep't  of  Agriculture 
buildings  at  Ottawa.  The  arrangement  is  shown  in  the  accompany- 
ing sketch.*  The  inlet  is  seen  at  E,  D  and  C. — a  U-shaped  pipe 
or  box  laid  in  the  ground,  the  deeper  the  better. 

The  intake  is  at  E  under  the  covered  outside  end  of  the  box, 


Hoard's  Dairyman,  June  5,  1908. 


9o 


CLEAN  MILK 


to  prevent  rain  and  snow  from  entering.  The  diameter  of  the  in- 
takes should  be  a  little  larger  than  the  outlets.  They  are  placed 
under  ground  so  that  the  air  is  of  more  even  temperature  and 
warmed  somewhat  in  winter  and  is  not  forced  in  by  wind  currents 
but  just  replaces  that  escaping  by  the  chimney.  This  should  be 
straight  and  in  the  top  of  the  roof  and  contain  a  damper,  F.  By 
closing  the  damper  air  ceases  to  enter  or  escape  from  the  ventila- 
ting system.  This  may  be  done  when  there  are  very  few  cows  in 
the  barn  or  in  extremely  cold  weather.    The  chimney  may  be  made 


<-*Qh..> 


'-&- 


Sketch  D — Showing  the  Rutherford  System  of  Ventilation.     (Hoard's  Dairyman.) 

of  a  metal  pipe  surrounded  with  sawdust  and  enclosed  in  a  wooden 
box,  to  prevent  moisture  forming  on  the  pipe.  The  diameter  of  the 
chimney  pipe  should  be  about  2  ft.  for  20  cows.  In  warm  climates 
there  is  no  need  for  any  method  of  stable  ventilation  other  than 
open  windows  and  doors. 

Cow  Stalls 


It  is  generally  considered  of  advantage  to  be  rid  of  stanchions 
and  tie-ups  of  all  kinds,  and  confine  the  cow  in  a  stall  giving  entire 


HOUSING  AND  CARE  OF  COWS  91 

'freedom  to  the  head.  The  swing  stanchion,  however  (p.  87), allows 
of  much  freedom  of  movement  and  is  a  good  form  of  tie.  The  par- 
titions between  the  cows  are  made  in  the  form  of  metal  or  wooden 
gates  about  five  feet  high,  but  not  touching  the  floor.  The  cows 
are  held  in  place  also  by  a  chain  or  rope  fastened  by  snap  hooks  to 
the  uprights  at  either  side  of  the  back  of  the  stall,  and  in  front  there 
is  a  movable  partition  of  metal  or  wood  adjusted  to  the  length  of 
the  cow,  so  as  to  keep  her  standing  well  back  to  the  edge  of  the 
manure  trench.  The  whole  length  of  the  stall  is  six  feet  to  six  feet 
eight  inches,  according  to  the  length  of  the  cow.  The  cow  is  fed  off 
the  floor,  or  from  a  gutter  cut  in  cement  inside  of  the  front  partition. 
Metal  stalls  are  comparatively  expensive.  The  chief  object  is  to 
keep  all  of  the  stall  structure  off  the  floor,  as  far  as  may  be,  to  have 
a  clean  floor-space  free  from  nooks  and  crannies  to  harbor  dirt  and 
dust.  The  width  of  the  cow  stall  varies  between  thirty-eight  to 
forty-five  inches,  according  to  the  size  of  the  animals.  The  milker 
opens  the  gate  of  the  stall  just  behind  him  when  milking,  which 
gives  him  more  room  and  keeps  the  next  cow  away  from  his  back. 

When  the  cows  are  let  out  the  chains  may  be  retained  in  place 
and  the  gates  are  opened.  For  details  and  illustrations  of  service- 
able stable  arrangements,  see  Appendix. 

It  is  well  to  round  up  the  cement  floor  to  a  point  six  inches  or 
so  up  the  wall  of  the  stable.  The  urine  should  be  drained  into  a 
tank,  which  can  be  emptied  once  or  more  daily,  or  be  received  into 
a  regular  drain  with  a  trap.  If  the  urine  cannot  be  so  removed  it 
is  well  to  have  the  gutters  tight  (without  outlet)  and  use  rotted  sod, 
sawdust,  or  leaf  mold  to  absorb  the  moisture  and  save  the  fertilizing 
properties  of  the  urine.  Chains  or  ropes  should  be  stretched  length- 
wise with  the  stable  under  the  cows'  necks  to  prevent  them  from 
lying  down  after  grooming  and  before  milking.  The  manure  must 
be  removed  as  soon  as  it  falls,  except  one-half  hour  before  or 
at  milking  time,  and  carried  not  less  than  several  hundred  feet  from 
the  barn,  so  as  not  to  attract  flies.    When  this  is  not  feasible,  by  us- 


92  CLEAN  MILK 

ing  absorbents,  as  above,  and  occasionally  sprinkling  5  per  cent, 
■creolin  solution  in  the  gutters  (if  of  wood),  the  stable  may  be  kept 
clean.  Sprinkling  woods  ashes  and  slaked  lime  in  the  trenches 
daily  after  removal  of  manure,  is  of  service.  The  germs  of  tuber- 
culosis escape  from  the  tuberculous  cow  chiefly  in  the  manure  and 
in  this  way  contaminate  the  milk — unless  great  cleanliness  is  used. 
Thus,  in  24  cows  apparently  healthy,  but  shown  by  the  tuberculin 
test  to  be  tuberculous,  Schroeder  found  40r"c  were  expelling  tubercle 
bacilli  in  the  manure ;  while  6  cows,  sick  some  3  years  with  tuber- 
culosis, were  all  thus  expelling  tubercle  bacilli.  This  is  still  another 
reason  for  the  avoidance  of  contamination  of  milk  with  manure. 
The  dried  manure  containing  tuberculous  germs  floats  about  in  the 
dust  of  a  barn  and  infects  healthy  animals  which  breathe  it  in. 

Experiments  performed  at  Washington  show  that  baboons  fed 
milk  from  tuberculous  cows  develop  tuberculosis  almost  as  rapidly 
and  as  certainly  as  when  tubercle  bacilli  obtained  from  a  tuberculous 
human  being  are  injected  into  the  animal.  This  proves  that  the 
baboon — and  presumably  man — is  as  susceptible  to  the  bovine  as 
to  the  human  type  of  tuberculosis  germ. 

Flies  convey  germs  to  the  milk  and  annoy  cattle.  The  average 
number  of  bacteria  carried  by  each  fly  is  about  one  million  and  a 
quarter,  as  shown  in  the  examination  of  414  flies  for  bacteria  at 
the  Storrs  Experiment  Station  (Bull.  51).  Where  there  is  a  pig 
pen  or  exposed  manure  pile  the  proportion  of  harmful  bacteria 
(coli-aerogenes  type)  is  very  large.  In  fact,  flies  are  the  chief 
source  of  the  contamination  of  milk  with  the  latter  type  of  germs, 
and  these  are  the  cause  of  diarrheal  diseases  and  infant  mortality. 
Therefore,  to  prevent  infant  mortality,  attack  the  fly  and  prevent 
its  contact  with  milk.  Many  of  the  preparations  for  spraying  cows 
with  the  purpose  of  keeping  off  flies  are  of  great  service,  and  are 
widely  advertised  in  the  agricultural  journals.  Shutters  are  useful 
in  hot  weather  to  darken  the  stable  and,  with  netting,  aid  to  keep 


HOUSING  AND  CARE  OF  COWS  93; 

out  flies.  Water  may  be  run  in  the  feeding  gutter  of  cement  floors, 
before  feeding  time,  or  supplied  in  iron  vessels  raised  from  the  floor. 

Before  sweeping  the  barn  floor  it  should  be  sprinkled  to  avoid 
dust,  and  neither  sweeping  nor  removal  of  manure  should  be  done 
within  half  an  hour  of  milking — to  prevent  contamination  of  the 
air.  While  most  of  the  germs  in  milk  come  from  dirt  on  the  cow, 
nevertheless  there  is  also  danger  of  contamination  from  dust  in  the 
barn.  For  this  reason  a  good  way  is  to  keep  a  barn,  built  with 
cement  floors,  entirely  for  milking  purposes.  The  floors  are 
sprinkled  and  the  cows  only  driven  in  the  building  at  milking  time 
and  removed  immediately  after.  In  the  air  of  the  ordinary  barn 
germs  are  fifty  per  cent,  more  abundant,  owing  to  the  dust  in  the 
air,  than  in  a  school  room  at  the  close  of  the  day. 

It  is  advisable  to  have  a  number  of  box  stalls  for  sick  animals, 
for  cows  about  to  have  calf,  and  for  calves.  These  should  be 
in  a  separate  stable,  because  contagious  diseases  may  thus  be  kept 
away  from  the  rest  of  the  herd,  as  contagious  abortion,  for  instance. 

A  milk  receiving  room  in  the  stable  is  useful,  in  which  the 
milk  from  separate  cows  may  be  weighed  and  recorded  before  the 
milk  is  carried  to  the  milk  room.      (See  Appendix,  page  320.) 

The  most  suitable  bedding  for  cows  in  the  production  of  clean 
milk  consists  either  of  shavings  from  kiln  dried  lumber  (which 
have,  in  the  process  of  kiln  drying,  been  sterilized),  or  sawdust, 
or  straw. 

We  have  been  laying  down  ideal  rather  than  the  essential  re- 
quirements in  the  housing  of  .cattle  to  secure  clean  milk.  Suppose 
we  take  an  ordinary  barn.  The  hay  is  probably  stored  over  the 
cows.  If  this  is  so,  then  either  the  hay  must  be  removed,  and  also 
the  ceiling  over  the  cows,  or  the  ceiling  must  be  made  dust-tight  and 
the  hay  never  removed  before  milking  time,  to  avoid  dust.  It  is 
probable  that  there  are  not  enough  windows.  More  windows,  or, 
better,  a  continuous  row  of  windows,  should  be  put  in.     There  will. 


94  CLEAN  MILK 

be  also  probably  unnecessary  feed  boxes  which  cannot  be  readily- 
cleaned,  rubbish  and  implements  and  dirt  to  be  removed. 

Everything  which  may  collect  dust  or  djrt  should  be  clone  away 
with.  The  whole  premises  then  should  be  washed,  swept  and 
painted  or  whitewashed.  The  material  sold  in  the  form  of  a  powder 
and  known  in  the  trade  as  water  paint,  and  which  is  mixed  with 
water  by  the  user,  is  not  much  more  expensive  than  whitewash  and 
is  infinitely  better.  The  floors  of  the  cow  stalls  must  be  smooth 
and  tight,  to  be  kept  clean,  and  may  be  of  matched  wood — although 
the  gutters  are  preferably  of  cement.  The  floor  of  the  stall  must 
not  be  too  long  or  too  short,  so  that  the  cow  when  up  will  just  stand 
on  the  edge  of  the  gutter.  If  the  cows  are  of  different  breeds  and 
sizes  this  may  be-regulated  by  arranging  the  ties  at  proper  distances 
from  the  gutter.  It  is  well  to  have  a  sufficient  space  behind  the 
gutters,  so  that  one  can  walk  without  being  soiled  with  manure, 
five  feet  at  least,  and  in  some  stables  this  space  is  made  wide  enough 
to  drive  a  wagon  for  filling  with  manure.  This,  however,  is  not 
necessary,  nor  the  best  way  to  remove  the  manure,  as  it  should  not 
be  allowed  to  collect  at  all.  The  gutters  must  be  deep  enough  (eight 
inches  or  more)  to  keep  the  cows  clean  when  lying  down,  or  may 
be  made  six  inches  deep  at  one  end  and  ten  inches  at  the  other  end 
of  the  barn  to  secure  a  fall  for  flushing  them  out  with  water.  They 
should  be  made  watertight.  It  is  well  to  keep  land  plaster  or  lime 
always  in  the  gutters  to  absorb  odors.  Extra  ventilation  may  be 
added  by  installing  one  of  the  systems  described  above  without 
great  expense. 

Feeding  should  only  be  done  after  milking.  A  sufficient  supply 
of  hot  and  cold  water  and  basins,  soap  and  towels  should  be  pro- 
vided in  a  convenient  place  for  the  milkers  to  wash,  and  this  may- 
be used  as  a  dressing-room.  No  manure  should  be  permitted  to 
remain  within  several  hundred  feet  of  the  barn,  and  the  ground 
about  the  barn  must  be  kept  clear  of  rubbish,  dirt  and  stagnant 


HOUSING  AND  CARE  OF  COWS  95 

water,  and  sprinkled  when  very  dusty.    Children  and  cats  and  dogs 
must  be  excluded  from  the  barn  at  milking  time. 

The  essentials  in  relation  to  the  stable,  then,  are :  Sufficient 
pure  air  and  light;  freedom  from  dust;  clean  floors,  gutters,  walls 
and  ceilings;  and  clean  surroundings,  free  from  manure  and  rubbish. 

Care  of  the  Cows* 

All  cows  should  be  tested  with  tuberculin -f  before  their  milk  is 
used  for  human  consumption,  either  as  raw  milk  or  in  the  form  of 
cream,  butter  or  cheese.  This  is  necessary,  since  no  expert  can 
tell  positively  by  the  appearance  or  examination  of  a  cow  whether 
she  is  tuberculous  or  not  in  many  cases.  A  tuberculous  cow 
may  even  be  very  fat.  If  tuberculous  cows  are  found  in  the  stable 
it  must  be  thoroughly  cleaned  and  disinfected  after  the  diseased 
cows  are  removed  and  before  healthy  animals  are  placed  in  the  stable 
(see  p.  346). 

Before  adding  new  cows  to  a  herd  it  is  safer  to  test  them  with 
tuberculin  twice;  once  before  purchase  and  again  after  three  months 
of  isolation  from  the  herd.  Then  if  the  cows  fail  to  react  they  may 
with  safety  be  added  to  the  herd.  Sometimes  cows  which  fail  to 
react  in  the  first  test  may  communicate  the  disease  to  the  herd  if 
at  once  turned  loose  with  the  herd  before  a  second  test.  The  neces- 
sity for  this  double  test  with  tuberculin  depends  upon  the  fact  that 
animals  may  not  react  in  a  very  early  or  latent  stage  of  tuberculosis 
and  again  that  animals  receiving  treatment  with  tuberculin  in  in- 
creasing doses  before  their  sale  may  not  at  that  time  react  to  an 
ordinary  test  dose.  New  cows  subject  to  the  double  tuberculin  test 
and  isolated  may  still  supply  certified  milk  after  the  first  negative 
test. 

The  germs  of  tuberculosis  have  been  frequently  found  in  milk, 
cream,  cheese  and  butter.  (Butter  may  harbor  active  tubercle  bacilli 
for  five  or  six  weeks.)     The  bacilli  of  tuberculosis  will  retain  their 


*  See  Moak's  "  Card  for  Identifying  Cattle,"  p.  357. 

f  For  directions  for  testing  cows  with  tuberculin,  see  p.  347. 


96  CLEAN  MILK 

virulence  in  ordinary  salted  butter  for  four  and  a  half  months  or 
longer;  in  cheese,  30  or  40  days,  (Schroeder  &  Cotton)  and  as 
tubercle  bacilli  are  found  in  about  one-fourth  of  samples  of  separ- 
ator slime  the  reasonable  inference  may  be  drawn  that  they  occur 
with  the  same  frequency  in  the  cream  from  which  the  butter  is 
made  and  therefore  in  25  per  cent,  of  butter. 

The  danger  of  consuming  milk  from  tuberculous  cows  is  seen 
more  conspicuously  in  children.  In  20  cases  of  primary  tuberculosis 
of  the  bowels  and  mesenteric  glands,  in  children,  13  were  caused  by 
the  bovine  germ  of  tuberculosis  and  7  by  the  human  type  of  the 
tuberculosis  germ.  In  16  children  with  tuberculous  glands  of  the 
neck,  10  of  the  cases  could  be  attributed  to  the  human  type  of 
tuberculosis  germ  and  6  to  the  bovine  form.  In  140  cases  of  tuber- 
culosis in  human  beings,  21  or  15%  were  derived  from  a  bovine 
source  (Steffenhagen).  The  distinction  between  tuberculosis  germs 
derived  from  bovine  and  human  sources  is  made  by  studying  the 
characteristics  of  the  germs  during  their  growth  outside  the  body 
upon  special  culture  media,  and  also  by  the  injection  of  the  germs 
into  animals.  The  bovine  bacillus  of  tuberculosis  when  injected  into 
cattle  and  the  lower  animals  is  much  more  virulent  than  the  human 
type. 

Recent  experiments  from  many  sources  (German  Commission 
and  British  Royal  Commission  on  Tuberculosis,  etc.)  appear  to 
show  that  in  tuberculosis  of  children  respectively,  10  and  23  per 
cent,  of  the  cases  are  due  to  the  tuberculosis  germ  peculiar  to  cattle 
(Bovine  tubercle  bacilli),  thus  locating  the  origin  of  10  to  23  per 
cent,  of  children's  tuberculosis  in  milk. 

In  the  light  of  most  recent  scientific  studies  and  experiments, 
tuberculosis  in  man  appears  to  start  more  frequently  in  the  digestive 
tract  than  was  formerly  supposed  even  when  the  disease  is  situated 
only  in  the  lungs  and  other  parts  of  the  body.  No  cow  should  be 
placed  in  a  herd  until  it  has  been  tested  and  found  free  from  tubercu- 
losis.    Such  testing  must  be  repeated  once  a  year,  or  twice,  if  there 


HOUSING  AND  CARE  OF  COWS  97 

has  been  much  tuberculosis  in  the  herd.  One  tuberculous  cow 
may  infect  the  entire  herd.  While  one  has  tuberculous  animals 
they  should  be  kept  in  a  separate  barn  from  healthy  animals.  Ac- 
cording to  the  present  New  York  State  law  tuberculous  cows  may 
be  kept  under  restrictions  according  to  what  is  known  as  the  Bang 
system.  That  is  tuberculous  cows  are  kept  in  a  separate  stable 
and  their  calves  removed,  as  soon  as  born,  and  fed  on  the  mother's 
milk  after  it  has  been  pasteurized  at  1850  F.  These  include  animals 
which  are  only  known  to  be  diseased  because  they  react  to  the  tuber- 
culin test,  while  those  cows  are  killed  which  show  physical  signs 
of  tuberculosis — especially  disease  of  the  womb,  udder,  and  lungs 
in  which  germs  are  spread  broadcast  by  discharge  from  the  womb, 
from  udder  to  milk,  and  in  manure  from  the  blood  or  from  swallow- 
ing of  discharge  coughed  from  lungs. 

When  the  calves  are  born  they  are  suckled  only  for  the  first 
day.  There  should  be  two  sets  of  barn  employees  if  possible ;  one 
for  the  tuberculous  and  the  other  for  the  healthy  animals.  Also 
two  sets  of  barn  utensils  of  every  kind.  The  stock  must  likewise 
be  separated  in  pasture  and  the  calves  tested  every  six  months  with 
tuberculin.  This  method  is  of  value  when  the  cows  are  valuable. 
Calves  should  not  be  allowed  in  a  stable  with  milch  cows  as  they 
may  spread  infection. 

The  milk  of  cows  which  are  being  tested  with  tuberculin  may 
be  used,  providing  that  they  do  not  react  to  the  test.  All  cows 
should  be  identified  by  metal  tags  in  the  ears  containing  a  number 
or  other  mark.  Such  tags  are  also  necessary  to  separate  those 
which  have  been  tuberculin-tested. 

Cows  with  garget  (having  caked  udders,  or  pus  (slime)  and 
blood  in  the  milk)  should  be  milked  by  one  who  does  not  milk  the 
other  cows,  and  animals  about  to  calve  should  be  kept  apart  from 
the  herd.  Milk  is  now  condemned  in  cities  which  is  found  to  con- 
tain an  excess  of  germs  (streptococci)  and  pus  from  inflamed, 
udders.    Diseased  udders  are  more  apt  to  be  found  immediately  be- 


98  CLEAN  MILK 

fore  and  after  calving  and  the  milk  from  cows  at  these  times  de- 
serves careful  watching.  In  view  of  the  wonderfully  successful 
results  from  the  use  of  air  for  inflating  the  udders  of  cows  suffering 
from  milk  fever,  it  will  be  wise  for  the  farmer  to  keep  the  simple 
apparatus  on  hand  for  practicing  the  treatment.  Every  agricultural 
paper  advertises  information  for  obtaining  and  using  the  apparatus. 
Cows  with  leaky  teats  are  especially  subject  to  bacterial  infection  of 
teats  and  should  be  removed  from  a  herd  supplying  certified  milk. 

The  hair  about  the  flanks,  udder,  and  the  brush  of  the  tail 
should  be  clipped  short  and  the  cows  groomed  once  or  twice  daily, 
if  necessary.  The  carding  and  brushing  is  done  after  milking,  or 
must  be  completed  two  hours  before  milking,  otherwise  the  dust 
produced  will  give  rise  to  an  increase  of  bacteria  in  the  milk.  In 
fact,  there  will  be  many  more  germs  in  the  milk  from  cows  brushed 
just  before  milking  than  would  occur  in  the  same  milk  if  the  cows 
had  not  been  brushed  at  all. 

Cows  may  be  washed,  however,  immediately  before  milking, 
provided  that  they  are  not  so  wet  as  to  drip.  This  should  always 
be  done  if  cows  are  soiled  with  manure  or  urine  in  a  moist  state, 
and,  in  some  certified  dairies,  all  the  cows  are  washed  in  a  special 
tank  for  the  purpose. 

This  is  not  at  all  essential,  and  the  writer  has  seen  great 
shrinkage  in  milk  caused  by  too  free  use  of  cold  water  applied  to 
cows  before  milking. 

Before  each  milking,  the  udder  should,  however,  be  wiped  with 
a  clean,  damp  towel,  or  washed,  if  necessary,  with  soap  and  water 
and  dried  with  a  dry  towel. 

The  towels  must  be  clean  and  the  water  pure  for  this  purpose. 
The  teats  and  udder  should  always  be  slightly  damp,  but  not  wet, 
during  milking.  If  the  udder  is  dry  so  much  dust  and  dry  skin 
falls  into  the  milk  that  the  number  of  germs  in  the  milk  is  much 
increased.  It  is  well  to  tie  up  the  cow's  tail  to  the  stall  while  milk- 
ing.    The  tail-holder  is  useful  in  fly  time.     A  tail-holder  is  applied 


HOUSING  AND  CARE  OF  COWS 


99 


to  each  cow  before  it  is  milked  and  at  the  same  time  one  is  also 
applied  to  the  cows  on  each  side  of  the  cow  which  is  to  be  milked. 
The  appliance  may  be  obtained  of  dairy  supply  firms.  Handling 
the  udder  stimulates  the  flow  of  milk.  So  that  the  udder  should 
be  cleaned  by  a  man  or  boy  especially  devoted  to  this  work,  who 


Fig-  3- 


Cow  Tail-holder. 

The  pincers  snap  around  the  cow's  tail  and  the  rubber  band  is  passed  around  the 
leg  and  hooked  into  the  open  link  on  the  chain.     (Bull.  104  Bureau  Animal  Industry.) 


goes  immediately  ahead  of  the  milker  with  pail  of  warm  water, 
wash  cloth,  soap  and  clean  towels.  He  can  thus  clean  as  many 
udders  as  would  require  ten  milkers  to  milk.  If  the  udders  are 
cleansed  some  time  before  milking  begins — as  by  the  milkers  them- 
selves— the  cows  are  apt  either  to  leak  their  milk  or  to  shrink  in 
milk-yield.     Do  not  allow  the  cows  to  become  excited  by  hard 


loo  CLEAN  MILK 

driving,  abusive  treatment  or  even  loud  talking.  The  cow  yard 
should  be  clean  and  dry.  If  it  is  deep  in  mud  it  is  impossible  to 
have  clean  cows. 

The  best  plan  is  to  allow  no  talking  whatever  to  the  cows  at 
milking,  and  then,  when  there  is  a  change  in  milkers,  it  will  not 
influence  the  animals  so  much. 

All  herds  from  which  a  clean  milk  supply  is  desired  should  be 
examined  by  a  competent  veterinarian  at  frequent  and  regular  inter- 
vals. Such  inspection  will  prevent  contamination  of  milk  with 
many  of  the  germs  most  dangerous  to  the  human  consumer,  because 
these  germs  are  derived  from  diseased  cows. 

Indeed,  veterinary  inspection  of  cows  is  as  much  more  valu- 
able than  laboratory  examination  of  their  product,  as  prevention, 
general! v  is  better  than  cure.     (See  p.  178.) 


CHAPTER  VI 


HANDLING  OF  MILK  AND  CREAM 


Milkers  and  Other  Employees 

*t    ■    A  HE  milker  should  be  clean  and  be  clean  shaven;  hair  on  the 

face  is  inadvisable.    Before  milking  and  before  putting  on 

his  milking  suit  he  must  wash  his  hands  thoroughly  with 

warm  water,  soap  and  a  nail  brush.     And  as  soon  as  the 

milker  has  finished  milking  a  cow,  and  poured  the  milk  from  his 

milking  pail  over  the  cooler,  he  should  wash  his  hands  again  before 

milking  another  cow.     The  hands  must  be  well  dried  on  a  clean 

towel  before  milking  is  begun.    Some  45  million  bacteria  were  found 

on  the  hand  of  an  ordinary  farm  worker  about  98  per  cent,  of 

"which  may  be  removed  by  thorough  washing  with  soap  and  warm 

"water.     (Storrs  Exper.  Station.) 

"i\  special  suit  of  clean,  washable  outer  garments  and  a  clean 
ivashable  cap  should  be  worn  during  milking  and  at  no  other  times. 
A  costume  consisting  of  a  white  duck  cap,  duck  trousers,  and  khaki 
shirt  with  leather  belt,  is  satisfactory.  The  suit  need  not  be  steri- 
lized, but  should  be  washed  twice  a  week.  When  not  in  use  they 
must  be  kept  in  a  clean  and  airy  place/  If  milking  is  done  after 
•dark  the  barn  must  be  well  lighted  or  the  milker  must  carry  a 
lantern.  This  is  very  objectionable  as  the  lantern  will  soil  his 
hands  with  oil  and  germs. 

Milking  ought  to  be  performed  at  the  same  hour,  morning 
sind  evening.     Milking  must  be  accomplished  quietly;  jerking  the 


102  CLEAN  MILK 

teats  causes  dirt  and  germs  to  drop  in  the  milk  and  is  not  per- 
missible.* The  first  few  jets  of  milk  from  each  teat  must  be  re- 
jected (not  on  the  floor,  but  into  a  special,  clean,  sterilized  small 
pail),  because  the  germs  are  washed  out  of  the  milk  cistern  by  the 

Fig.  4. 


Good  type  of  Milking  Suit  and  Pail.     (Bull.  41  Hygienic  Lab.) 

first  part  of  the  milk.     If  any  of  the  milk  in  the  pail  becomes  con- 
taminated through  accident  or  through  mixture  with  stringy  or 


*  For  more  detailed  account  of  milking  and  use  of  milking  machine,  see 
Appendix,  336. 


HANDLING  OF  MILK  AND  CREAM 


[03 


bloody  milk  from  the  udder,  the  whole  must  he  thrown  away. 
Milking  stools  must  be  clean;  iron  stools,  painted  white,  are  recom- 
mended (see  Figs.  5  and  6),  or  the  use  of  a  milk  pail  as  a  seat  (see 
Fig.  9,  page  105). 

After  the  milker  has  donned  his  milking  suit  and  cap  and 
washed  his  hands,  he  should  touch  absolutely  nothing  but  the 
cleaned  teats  of  the  cow  and  his  clean  stool  and  milk  pail.  The 
habit  of  milkers  wetting  their  hands  with  milk  is  not  to  be  tolerated. 

No  person  employed  to  milk,  or  handle  milk  in  any  way,  should 
have,  or  have  come  in  contact  with,  any  contagious  disease.  In 
case  of  illness  in  the  household  of  an  employee  a  physician's  certifi- 


Fig.  6. 


Fig.  5. 


Iron  Milking  Stool. 


Milking  Stool. 


cate  should  be  required  of  the  employee  stating  that  the  illness  is 
not  communicable  before  permitting  the  employee  to  come  in  contact 
with  milk  in  any  manner. 

The  safest  rule  is  to  debar  a  person  from  handling  milk  who 
has  tuberculosis,  syphilis,  severe  diarrhea,  or  suppurating  sores  on 
the  surface  of  the  body,  throat  trouble  or  any  infectious  disease,  or 
has  come  in  contact  with  a  patient  suffering  from  contagious  dis- 
order, or  entered  a  dwelling  in  which  there  has  been  contagious 
disease. 

If  a  cow  has  one-quarter  of  the  udder  inflamed  so  that  pus 
(slime)  or  blood  escapes  from  it  into  the  milk,  the  milk  from  the 
whole  udder  is  unfit  for  human  consumption.     The  cow  should  be 


ic>4 


CLEAN  MILK 


isolated,  and  the  milk,  after  boiling  for  15  minutes,  may  be  fed  to 
animals. 

The  milk  pail  is  an  important  factor  in  the  production  of  clean 
milk.  The  writer  first  employed  a  pail  which  has  a  removable  cover 
crowned  up  so  that  it  is  about  four  inches  above  the  top  of  the  pail, 
with  a  hole  in  the  cover  six  inches  in  diameter.  The  pail  has  a  spout 
arising  from  its  upper  part  and  reaching  a  little  above  the  cover  of 
the  pail  when  it  is  in  place.  The  spout  on  the  pail  is  covered  by  a 
removable  metal  cap. 

Two  layers  of  sterilized  cheesecloth  or  cotton  flannel  are 
placed  across  the  top  of  the  pail  and  then  the  cover  is  fitted  on  over 


Fig.  8. 


Fig-  7- 


The  Gurler  Milk  Pail. 


A  recent  improvement  of   the  Gurler  Pail. 


the  top  of  the  pail,  stretching  and  holding  the  cheesecloth  in  place. 
When  the  pail  is  full  it  may  be  emptied  through  the  spout  without 
disturbing  the  cheesecloth,  and  so  be  used  through  a  whole  milking. 
The  gauze  (or  flannel)  is  washed  in  warm  water,  then  in  soda  and 
water,  and  rinsed  in  cold  water  and  boiled  20  minutes,  or  placed  in 
the  steam  sterilizer  before  being  used  again.  It  is  better  to  use  it 
at  but  one  milking  and  throw  it  away.  The  Gurler  milk  pail  (Fig. 
7)  is  very  similar,  with  a  removable  cover,  the  opening  in  which 
is  larger  than  it  need  be,  however.  Otherwise  it  is  a  very  satis- 
factory pail.     Cheesecloth  is  laid  over  the  top  of  the  pail  and  the 


HANDLING  OF  MILK  AND  CREAM  105 

cover  is  fitted  on,  stretching  it  into  place.  Experiments  have  shown 
that  milking  through  a  clean  cheesecloth  strainer  is  capable  of 
3'ielding  a  comparatively  clean  milk,  even  in  rather  dirty  premises. 
The  writer  has  recently  known  excellent  results  with  the  use 
of  a  milk  pail  modified  from  one  described  by  Stewart  of  Phila- 
delphia. This  is  made  of  spun  steel,  iol/2  inches  high,  and  is  cov- 
ered with  a  flat,  removable  lid  on  which  the  milker  sits.  The  milk- 
ing is  done  into  a  spout  which  has  an  expanded  opening  7  inches 
in  diameter.    The  spout  is  covered  at  the  end  by  a  removable  pan„ 

Fig.  9. 


•ffcifxtt 


Modification  of  Stewart's   Milk   Pail. 

and  the  bottom  of  the  pan  is  a  wire  strainer — 100  meshes  to  the 
inch.  The  opening  of  the  spout  is  nearly  vertical,  so  that  dirt  will 
not  easily  fall  into  it.  Any  metal  worker  can  make  such  a  pail. 
Stewart's  pail  may  now  be  procured  of  the  Star  Milk  Cooler  Co. 
Stewart  found  that  milk  in  this  pail  contained  only  29  germs,  as 
against  125,000  germs  to  the  quarter  teaspoonful  of  milk  drawn, 
into  an  open  bucket. 

Milk  pails  should  have  all  seams  covered  smoothly  with  solder. 
The  aluminum  pail  is  best  because  made  in  one  piece  without  joints. 


io6 


CLEAN  MILK 


Stocking  *  gives  the  following  summary  of  results  of  experi- 
ments with  covered  pails  and  strainer  cloths : 

i.  The  use  of  the  covered  milk  pail  is  of  great  advantage  in 
any  stable  in  excluding  dirt  and  bacteria  from  the  milk.  The  rel- 
ative advantage  gained  by  the  use  of  the  cover  depends  upon  the 
sanitary  condition  of  the  stable. 

2.  The  special  form  of  cover  does  not  seem  to  be  important 
provided  it  is  a  device  practical  for  use  and  the  area  through  which 
dirt  can  gain  access  to  the  milk  is  reduced  as  much  as  possible. 


Fig.  ii. 


Fig.  10. 


Stadmueller  Covered  Pail. 
(Bull.  48  Storrs  Exper.  Sta. 


The  North  Covered  Milk  Pail. 
(Bull.  4S  Storrs  Exper.  Sta.) 


3.  Whether  or  not  a  strainer  on  the  covered  pail  is  desirable 
depends  upon  the  style  of  the  straining  device. 

4.  The  use  of  the  strainer  in  a  pail  where  the  dirt  which  falls 
into  the  opening  is  likely  to  be  driven  through  by  the  succeeding 
streams  of  milk  is  not  desirable  (Stadmueller,  Fig.  10).  Its  use 
tends  to  increase  the  germ  content  of  the  milk  and  injure  its  keep- 
ing quality. 


•Bull.  No.  48  Storrs    Agric.  Exper.   Sta. 


HANDLING  OF  MILK  AND  CREAM 


107 


5'.  In  pails  where  the  dirt  which  falls  in  does  not  remain 
where  the  succeeding  streams  strike  against  it  a  strainer  cloth  aids 
in  keeping  down  the  number  of  bacteria  which  gain  access  to  the 
milk.    The  North  pail  (Fig.  11),  is  an  illustration  of  this  type. 

6.  The  use  of  absorbent  cotton  as  a  strainer,  as  in  the  Gurler 
pail,  is  a  decided  advantage  in  preventing  the  entrance  of  bacteria 
into  the  milk. 

The  metal  strainer  is  safer  where  milkers  are  unreliable,  as 
they  will  handle  cheesecloth  strainers  and  lay  them  down  in  dirty 

Fig.  12. 


The  Trueman  Covered  Milk  Pail.  One  of  the  simplest  and  best  covered  pails. 
Made  in  one  piece,  easily  cleaned  and  does  not  have  any  strainer.  (Bull.  48  Storrs 
Exper.  Sta.) 


places.  Cotton  wool  (absorbent  cotton)  laid  between  two  layers  of 
cheesecloth  to  strain  milk — while  milking — into  the  pail,  is  more 
effective  than  cheesecloth  alone,  but  we  have  found  that  the  cot- 
ton wool  is  matted  in  lumps  by  the  jets  of  milk  and  that  only  those 
absorbent  cotton  strainers  made  by  dairy  supply  companies  for  the 
purpose  are  to  be  recommended.  We  have  been  content  with  the 
good  results  obtained  from  cheesecloth  alone. 

By  a  new  invention  one  may  do  away  with  the  small  mouthed 
milk  pail  and  at  the  same  time  save  the  expense  and  trouble  of 


io8 


CLEAN  MILK 


changing  the  cheesecloth  filter  after  each  cow  is  milked.  This  new 
appliance  is  known  as  the  Revolving  Dairy  Filter  (Fig.  13). 
Briefly,  the  principle  is  as  follows:  There  are  two  parts.  1.  A 
reservoir  to  catch  the  milk  which  may  be  attached  to  an  ordinary- 
open  milk  pail.  2.  A  revolving  disc  attached  to  the  under  surface 
of  the  reservoir.  The  cow  is  milked  into  the  reservoir  and  the  milk 
passes  through  an  opening  one  inch  in  diameter  in  the  bottom  of 
the  reservoir  through  three  thicknesses  of  cheesecloth  and  through 
holes  in  the  revolving  disc  into  the  pail. 

After  each  cow  is  milked  the  disc  is  turned  by  a  handle  so  that 
a  fresh  portion  of  cheesecloth  and  a  new  opening  of  the  perforated 

Fig.  13. 


Revolving  Dairy  Filte; 


•disc  is  brought  opposite  the  single  1  inch  hole  in  the  reservoir.  In 
this  way  eight  cows  may  be  milked  with  a  fresh  filter  surface  for 
each  cow  and  using  the  same  milk  pail.  The  opening  through  which 
the  milk  passes  is  also  smaller  than  in  any  small  mouthed  milk  pail. 
As  compared  with  the  open  pail  more  than  three  quarters  of  the 
bacilli  are  removed  by  this  filter.  It  is  readily  cleaned  and  sterilized 
and  is  cheap.* 

For  farmers  using  little  care  in  cleaning  their  cows  and  large 
mouthed  milk  pails  the  revolving  filter  is  certainly  to  be  recom- 
mended. 


Revolving  Dairy  Filter  Co.,  53  Union  St.,  Portland,  Maine. 


HANDLING  OF  MILK  AND  CREAM  109* 

But,  if  cows  are  properly  cleaned  and  their  udders  dampened 
before  milking,  it  is  probable  that  a  simple  Trueman  pail  is  the  best 
pail  of  all  those  described  and  is  without  any  filter  whatever.  The 
area  on  which  dirt  may  fall  is  somewhat  larger  (6  in.)  in  the  re- 
volving filter  than  in  a  small  mouthed  pail.  Its  use  also  adds  an- 
other article  to  cleanse  and  it  is  in  itself  another  possible  source  of 
bacteria  if  not  perfectly  sterilized. 

The  handling  of  milk  may  be  conducted  properly  in  many  ways. 
Some  of  these  are  very  simple  and  inexpensive;  others,  which  are 
quite  expensive  and  elaborate,  are  required  for  convenience  and. 

Fig.  14- 


Metal  frame  on  which  milk  pails  are  set  in  the  stable  to  keep  them 
out  of  the  dirt.     (Storrs  Bull.  48.) 

certainty  when  large  quantities  of  milk  are  to  be  handled  in  the  most: 
approved  style. 

To  such  a  degree  of  refinement  has  this  matter  been  carried, 
and  such  a  multitude  of  utensils  have  been  devised,  that  the  inex- 
perienced, would-be  dairyman  is  disheartened  at  the  very  outset  by 
the  great  number  of  appliances  which  he  finds  are  alike  recom- 
mended and  reviled  by  his  various  advisers.  The  matter  of  the  best 
way  to  handle  milk  is  a  source  of  constant  study,  and  improvements 
are  as  constantly  taking  place,  and  while  there  will  never  be  a  time 
when  competent  men  will  all  agree  on  special  details,  yet  they  are 
agreed  on  the  principles  and  essentials  of  the  business.  We  have- 
already  described  the  principles,  and  dwelt  upon  the  facts  which 


no  CLEAN  MILK 

have  led  up  to  the  establishment  of  those  principles;  we  now  pro- 
pose to  devote  our  attention  to  the  essentials  in  handling  clean,  pure 
milk.  First :  We  will  consider  those  essentials  necessary  to  insure 
the  continuance  of  the  cleanliness  of  the  milk  until  it  reaches  the 
consumer,  and  then  the  various  devices  for  convenience,  labor- 
saving  and  system  required  in  handling  large  quantities  of  milk  in 
the  best  manner  known  at  the  present  time — always  with  the  ad- 
mitted possibility  of  improvement  in  details. 

The  milk  room  is  the  first  essential.  It  must  be  clean,  proof 
against  dust  and  extreme  weather  conditions,  and  separate  from 
barn  and  house.  It  need  not  be  expensive  or  elaborate.  The  floor, 
although  preferably  of  asphalt  or  cement,  may  be  of  oiled  or  painted 
wood  (if  smooth  and  tight),  and  if  on  the  level  with  the  bottom  of 
the  milk  wagon,  will  make  it  easier  in  loading  the  milk. 

All  water  and  washings  from  the  room  must  be  carried  away 
in  pipes  to  a  point  fifty  yards  from  the  milk  house. 

The  milk  room  should  be  surrounded  by  grounds  free  from 
rubbish,  pools  of  milky  water,  or. dust  (fifteen  grains  of  dust  have 
been  shown  to  contain  as  many  as  seventy  million  germs),  and 
should  be  at  least  forty  feet  from  the  barn. 

It  must  be  well  lighted,  with  mosquito  screens  at  the  windows 
and  doors.  The  windows  and  doors  should  be  closed,  as  far  as 
possible,  at  the  time  the  milk  is  handled  in  the  house,  to  exclude 
dust — ventilation  being  obtained  by  the  King  system.  If  there  is 
a  closed  porch  or  vestibule,  it  will  be  an  added  safeguard  against 
the  admission  of  dust  in  windy  weather,  by  providing  an  entrance 
with  double  doors.  The  construction  of  the  milk  room  may  be  of 
wood,  with  walls  and  ceiling  of  wood  or  plaster,  preferably  painted. 
Whitewash  may,  however,  be  used  on  the  inside  of  the  room  and 
should  be  renewed  every  three  months.  Scrupulous  cleanliness 
must  be  observed  in  the  milk  room,  and  it  should  be  kept  as  dry  as 
possible  in  all  its  parts,  with  no>  spots  of  mold  on  the  walls.  No 
sour  milk  should  be  left  in  the  room,  as  the  sour  milk,  or  lactic  acid. 


HANDLING  OF  MILK  AND  CREAM  nr 

germs,  will  get  into  the  fresh  milk.  The  milk  room  ought  not  to 
be  used  for  any  other  purpose  than  to  handle  the  milk,  and  should 
contain  nothing  that  is  not  required  in  handling  milk. 

When  milk  is  to  be  shipped  in  cans,  the  following  utensils  are 
essential : 


Milk  pails. 

Receiving  tank  or  cans. 

A   strainer. 

A  cooler  or  aerator. 

A    collecting    can. 

Shipping  can  with  all  seams  flushed  with  solder. 

A  tank  for  washing  purposes. 

A  tank  for  immersing  cans  in  cold  water. 

Also  washing  soda  or  soap  powder,  brushes  to  scrub  utensils  and  inside  of 

cans,  and  cheesecloth  for  straining  purposes. 
Pure  hot  and  cold  water,  and  steam  if  business  is  conducted  upon  a  large 

scale. 


Method  of  Handling  Milk  To  Be  Shipped  in  Cans 

Cooling  the  Milk. — I  cannot  agree  with  such  authorities  as 
Dr.  Chapin,  of  New  York  (than  whom  no  one  has  done  more  to 
introduce  clean  milk  into  that  metropolis),  when  he  says  on  page 
131  in  his  book  on  "  Infant  Feeding  "  :  "  For  cooling  the  milk  to 
best  advantage  a  can  placed  in  ice  water  is  better  than  the  com- 
mercial coolers." 

Clean  milk  calls  for  milk  cooled  to  below  500  F.  with  an  hour. 
This  will  not  be  accomplished  by  placing  milk  warm  from  the 
cows  into  large  cans  and  then  immersing  the  cans  in  ice  water,  un- 
less by  constant  stirring  of  the  milk  in  each  can.  Warm  milk 
placed  in  quart  bottles  and  immersed  in  ice  water  can  be  cooled 
properly — that  is,  to  45  °  F. — within  the  hour.  When  milk  is  ob- 
tained from  cows  giving  milk  varying  greatly  in  composition,  as  is 
usually  the  case,  it  must  be  thoroughly  mixed  before  bottling. 
Rut,  inasmuch  as  half  an  hour  or  more  is  commonly  required  to 
milk   sufficient   milk  to  mix,   and  inasmuch   as   one   cannot   keep 


ii2  CLEAN  MILK 

warm  milk  for  this  period  without  great  increase  in  germs,  the 
only  way  is  to  cool  each  pailful  as  soon  as  it  is  milked. 

Then  the  milk  may  be  kept  an  hour  or  more  before  it  is  mixed 
and  bottled.  I  started  out  prejudiced  in  favor  of  cooling  milk  by- 
immersion  of  cans  or  bottles  in  ice  water,  but  did  not  find  it 
practicable,  except  under  certain  conditions  (see  p.  118).  There  is 
no  doubt  but  that  the  cooler  and  all  apparatus,  not  necessary  in 
handling  milk,  should  be  abandoned  when  possible.  The  oftener 
milk  touches  objects  the  more  likely  will  contamination  result,  es- 
pecially by  aeration  in  a  dusty  atmosphere.  But  immediate  cooling 
is  essential. 

When  milking  begins,  as  soon  as  a  milk  pail  is  filled,  the  milk 
should  be  taken  directly  to  the  milk  house  and  the  milk  poured  into 
the  strainer,  which  is  placed  in  the  receiving  tank  of  the  cooler. 
The  milk  runs  over  the  cooler  and  is  received  in  the  shipping  can, 
which,  when  filled,  should  be  immersed  in  a  tank  of  cold  or  iced 
water  above  the  shoulder  of  the  can  with  the  cover  of  the  can  left 
off  until  shipping  time.  The  milk  should  be  cooled  below  500  F. 
Two  types  of  coolers  or  aerators  are  in  common  use.  Aeration,  or 
exposure  of  the  milk  to  air,  is  not  essential  if  the  milk  is  with- 
drawn from  the  cow  in  a  cleanly  manner,  but  if  the  milk  is  more 
or  less  contaminated  with  manure,  by  impure  air  or  by  odors  caused 
by  imperfect  feeding,  aeration  frees  it  to  an  extent  of  so-called 
animal  odor.  Aeration  is  inadvisable,  in  so  far  as  the  milk  is  ex- 
posed to  germs  in  the  air  during  the  process.  The  coolers  in  ordi- 
nary use  do,  however,  aerate  the  milk  at  the  same  time  that  the 
milk  is  cooled.  The  conical  cooler  (Fig.  15)  may  be  employed  when 
a  moderate  quantity  of  milk  is  to  be  handled,  but  requires  more 
labor,  as,  in  order  to  cool  the  milk  satisfactorily,  the  water  in  the 
aerator  must  be  constantly  stirred  to  continually  change  the  layer 
of  water  lying  against  the  inner  surface  of  the  tin  over  which  the 
milk  runs.  This  aerator  is  fitted  with  an  inflow  and  outflow  pipe 
for  running  water,  at  either  side  of  the  base  of  the  aerator,  but- 


HANDLING  OF  MILK  AND  CREAM 


ii3 


unless  the  water  is  near  the  freezing-  point,  it  is  better  to  fill  the 
aerator  with  cracked  ice,  salt  and  water.  In  this  case  the  aerator 
may  be  simply  used  as  a  storage  tank  for  ice  water,  and  both  the 
inflow  and  outflow  pipes  are  closed.  By  constant  stirring  of  the 
ice  water  in  the  aerator  while  the  milk  is  flowing,  it  is  possible  to 
reduce  the  temperature  of  the  milk  coming  from  the  cooler  to  below 
500  F.  In  this  style  of  aerator  the  milk  flows  from  the  reservoir 
at  the  top  through  fine  holes  all  about  the  base  of  the  reservoir  out 

Fig-  15. 


The   Conical   Cooler. 

on  to  the  surface  and  corrugations  of  the  cooler,  collects  in  the 
gutter  below,  and  is  carried  off  by  the  pipe  leading  from  the  gutter 
(in  the  front  of  the  aerator  in  the  cut)  into  the  shipping  can.  Often 
these  holes  are  too  large  or  too  numerous,  allowing  the  milk  to 
flow  too  fast,  when  some  must  be  closed  by  solder.  This  kind  of 
aerator  works  very  unsatisfactorily  if  the  water  is  not  constantly 
stirred,  and  is  not  to  be  recommended  if  running  water  is  at  com- 
mand and  permits  of  use  of  a  Star  or  tubular  cooler. 


ii4 


CLEAN  MILK 


The  Star  cooler  (Fig.  16),  or  that  of  the  tubular  variety  (Fig. 
17),  are  by  far  the  most  efficient,  certain  and  convenient  coolers, 

Fig.  16. 


Star  Cooler. 


although  more  expensive   in  first  cost   than  the  conical  aerators. 
The  much  greater  surface  offered  by  the  tremendously  corrugated 

Fig.  17. 


SPRIKO  WATER 
DISCHARGE 


SPRING  WETET& 
SUPPLY 


Tubular  Cooler. 

form  of  the  cooler,  together  with  the  forced  circulation  of  water 
which  flows  continuously  from  below  upward  through  the  cooler, 
account  for  the  superiority  of  this  type  of  cooler. 


HANDLING  OF  MILK  AND  CREAM 


15 


The  temperature  of  the  milk  may  be  lowered  to  a  point  two 
'degrees  above  that  of  the  water  circulating  through  the  cooler. 

The  Star  cooler  is  made  of  two  sheets  of  corrugated  copper, 
tinned  on  its  outer  surface,  which  comes  in  contact  with  the  milk. 
The  water  enters  below,  filling  the  entire  space  between  the  copper 
sheets,  and  flows  upward  through  the  cooler,  while  the  warm  milk 
drops  through  the  holes  punched  along  the  whole  length  of  the  feed 
trough  at  the  top  of  the  cooler  and  flows  down  over  both  cooling- 
sheets.  As  the  milk  is  cooled,  flowing  down  the  outside,  the  water 
is  warmed  as  it  moves  up  the  inside  of  the  cooler  (see  Fig.  16). 


Fig.  18. 


Fig.  19. 


Star  Milk  Cooler. 


Star  Milk  Cooler. 


The  water  supply  for  the  cooler  may  be  obtained  in  various 
ways :  From  a  common  source  of  water,  as  a  town  supply ;  from  a 
barrel  or  tank  over  the  cooler  (see  Fig.  18)  ;  or  from  a  barrel  be- 
neath the  cooler  by  means  of  a  siphon  attachment  (see  Fig.  19).  If 
it  be  desired  to  cool  the  milk  much  under  50°,  it  may  be  necessary 
to  use  ice  water  in  a  part  of  the  cooler. 

This  is  most  economically  accomplished  by  an  ice  water  sec- 
tion, which  is  made  to  be  hung  on  the  bottom  of  the  Star  cooler 
and  is  practically  a  small  counterpart  of  the  larger  cooler  above 


n6 


CLEAN  MILK 


(Fig.  20).  Ice  water  is  run  through  the  ice  section  alone  and  isr- 
obtained  from  an  overhead  barrel  holding  broken  ice,  over  which 
water  is  sprayed  from  a  large-surface  nozzle,  and  flows  from  the 
barrel  through  a  short  hose  through  the  ice  water  section. 

A  similar  result  may  be  secured  by  using  a  tubular  cooler 
(Fig.  17),  arranged  so  the  general  water  supply  may  be  run  through 
the  upper  half  of  the  cooler,  and  the  ice  water  or  cold  brine  through 
the  lower  half.  By  either  of  these  contrivances  milk  may  be^ 
reduced  to  a  temperature  below  400. 


Fig.  20. 


COPVBIOHT,  190S, 

Star  Milk  Cooler. 


In  place  of  the  spray-head  for  sprinkling  water  on  cracked  ice 
in  a  barrel,  to  supply  the  ice  water  section  of  the  Star  cooler,  it 
lias  been  found  (by  my  friend  Mr.  Paulhamus,  of  Sumner,  Wash.) 
that  the  following  arrangement  is  better:  A  medium-sized  cask  is 
lined  from  top  to  bottom  with  a  coil  of  a  hundred  feet  or  more  of 
half-inch  pipe.  The  water  supply  is  connected  with  the  bottom  of 
the  coil,  and  the  top  of  the  coil  is  connected  with  the  ice  water 
section  of  the  Star  cooler.  Large  pieces  of  cracked  ice  are  used  to 
fill  the  cask  to  the  top,  to  which  may  be  added  rock  salt  and  then 
water.     If  salt  is  used,  care  must  be  taken  to  have  the  water  run- 


HANDLING  OF  MILK  AND  CREAM 


117 


n'mg  constantly  through  the  coil  in  the  cask,  otherwise  the  water 
will  freeze  in  the  coil.  This  way  of  cooling  the  water  supply  for 
the  water  section  of  the  Star  cooler  is  both  more  convenient  and 
satisfactory  because  the  cask  may  be  placed  directly  on  the  floor  of 
the  milk  room,  instead  of  up  in  the  air  as  required  for  the  sprinkler, 
•and  much  less  ice  is  used  than  when  a  sprinkler  is  employed. 

The  advantages  of  such  arrangements  consist  in  utilizing  the 
natural  temperature  of  the  regular  water  supply  of  the  dairy  to  do 
the  chief  part  of  cooling  the  milk,  while  the  ice  water  is  only- 
required  to  complete  the  smaller  part  of  the  reduction  of  tempera- 
ture in  hot  weather.     There  are  many  different  sizes  of  both  the 


|G00LE.R 

Trap  Milk  Strainer. 


conical,  tubular  and  Star  coolers  adapted  to  the  quantity  of  milk 
which  is  handled.  The  tubular  coolers  are  constructed  to  with- 
stand high  water  pressure,  while  the  Star  coolers  are  not. 

While  milk  may  be  simply  poured  from  the  milking  pails 
through  two  or  three  thicknesses  of  cheesecloth,  or  through 
one  layer  of  cotton  flannel,  into  a  receiving  can,  from  which  it  is 
transferred  to  the  receiving  tank  of  the  cooler,  a  better  form  of 
strainer  is  the  trap  variety  (see  Fig.  21),  which  is  placed  in  the 
receiving  tank  of  the  cooler.  The  milk  is  poured  into  the  upright 
funnel,  and  has  to  rise  from  below  up  through  the  cheesecloth 
strainer  to  seek  its  level. 

Particles  of  dirt  and  foreign  matter  would  naturally,  through 


Ii8  CLEAN  MILK 

gravity,  fall  to  the  bottom  of  the  vessel  and  not  be  forced  through 
with  the  milk,  as  commonly  happens  when  milk  is  poured  from 
above  through  a  strainer. 

In  regard  to  straining  milk.  Every  additional  utensil  adds 
another  possible  medium  for  the  conveyance  of  germs  to  milk.  Too 
great  emphasis  cannot  be  put  upon  this  point — i.  e.,  the  necessity  for 
the  use  of  as  few  utensils  as  possible.  When  the  cows  are  thor- 
oughly clean  it  is  not  essential  to  have  any  strainer  upon  the  milk 
pail  at  all,  and  the  only  straining  of  the  milk  may  be  done  through 
two  single  thicknesses  of  sterilized  cheesecloth  with  a  layer  of  sterile, 
absorbent  cotton  between  these.  This  straining  is  done  when  the 
milk  is  poured  into  a  receiving  can  for  mixing  the  warm  milk  or  into 
the  receiving  can  of  the  cooler. 

The  strainer  cloths  used  over  the  milk  pails  and  other  utensils 
may  be  of  various  materials.  The  writer  has  employed  chiefly 
cheesecloth  or  rather  gauze  (which  is  cheesecloth  prepared  by 
washing,  to  remove  the  sizing  and  impurities,  and  dried),  of  the 
finest  mesh,  and  two  layers  in  thickness. 

A  single  thickness  of  coarse  cotton  flannel  or  Turkish  towelling 
may  be  used,  however.  When  the  strainer  cloth  cannot  be  steri- 
lized in  a  regular  sterilizer,  it  should  be  boiled  for  twenty  minutes 
wrapped  in  a  towel  or  clean  cloth  and  left  enclosed  in  this  wrapping 
until  used.  Then  it  should  be  removed,  but  the  fingers  should  not 
touch  that  part  of  the  strainer  cloth  which  will  come  in  contact  with 
the  milk.  Before  sterilizing  the  cloth,  it  should  be  well  rinsed  in 
cold  water,  washed  in  hot  water  and  washing  soda,  and  rinsed  in 
cold  water  again.  Every  little  detail  must  be  carried  out  con- 
scientiously, as  one  failure  in  caring  for  the  milk  properly  will 
spoil  the  result  entirely. 

The  simplest,  cleanest  and  most  inexpensive  method  of  hand- 
ling milk  is  to  place  it — as  soon  as  milked — in  a  bottle-filler  tank 
and  run  it  at  once  into  bottles  and  immerse  the  bottles  in  ice  water. 
By  this  method,  the  need  of  a  cooler  is  avoided  and  the  chance  of 


HANDLING  OF  MILK  AND  CREAM 


119 


germs  getting  into  the  milk  during  its  exposure  to  the  air  in  running 
over  the  cooler.  The  chief  objections  to  this  method  are  two. 
(1)  That  the  milk  is  not  cooled  so  rapidly,  and  (2)  that  the  milk 
will  not  be  uniform  in  composition.  The  first  objection  is  of  no 
weight  if  the  milk  is  clean;  that  is,  bacteria  will  not  multiply  in 
clean  milk  while  it  is  cooling  in  the  bottle. 

The  objection  to  lack  of  uniformity  in  composition  is  very  real 
and  important.  As  mixing  milk  is  not  done  in  the  bottling  tank  the 
cows  should  yield  milk  of  pretty  uniform  quality,  otherwise  the  milk 

Fig.  22. 


Covered  Milk  Cooler.      (Bureau  of  Animal  Industry,  Bull.   104.) 


in  different  bottles  will  vary  very  considerably,  as  the  milk  is  bottled 
as  soon  as  it  is  withdrawn  from  the  cows.  If  there  are  a  number 
of  milkers  and  the  milk-yield  of  the  different  cows  is  similar  in 
composition,  then  the  method  is  ideal  in  its  simplicity  and  its  free- 
dom from  expensive  and  contaminating  apparatus.  The  milk  will 
be  cooled  to  45 °  F.  in  ice  water  in  an  hour  and  by  no  method  will 
the  cream  rise  more  rapidly.  Another  method  of  overcoming1  the 
danger  of  the  tremendously  thorough  exposure  to  the  air  of  milk 
passing  over  the  ordinary  coolers  is  the  covered  cooler  and  bottle 
filler  (see  Fig.  22  and  Fig.  23). 


120 


CLEAN  MILK 


This  arrangement  is  particularly  applicable  in  milk  rooms  whicK 
cannot  be  sterilized  by  steam  and  in  which  the  air  may  be  con- 
taminated by  dust  and  germs. 

Its  simplicity  and  moderate  cost  are  also  attractive  features.  It 
is  said  that  one  man  can  fill  and  cap  two  to  three  hundred  bottles  in 
one  hour  with  the  appliance,  and  that  it  is  suitable  for  a  herd  of 

Fig.  23 


Parts  of  Cooler. 

1.  Cooler  proper.  Water  passes  through  interior  of  coil,  and  milk  over  outer 
surface.  2.  Receptacle  placed  on  top  of  No.  1  ;  has  perforations  in  the  bottom 
near  the  edge  for  distributing  milk  over  the  cooler.  3.  Cover  inclosing  cooler. 
4.  Receptacle  for  receiving  the  milk  and  which  also  contains  the  strainer.  The 
latter  consists  of  a  perforated  plate  which  is  put  in  first ;  next  to  this  is  placed  a 
layer  of  cheese  cloth,  then  a  layer  of  absorbent  cotton  followed  by  another  layer 
of  cheese  cloth  and  a  perforated  plate.  5.  A  copper  ring,  filled  with  lead  and 
heavily  tinned,  placed  on  top  of  parts  of  strainer  to  hold  them  in  position.  (Bureau 
of  Animal  Industry,  Bull.  104.) 


fifty  cows  and  should  not  cost  over  $150.00  (Bull.  104,  Bureau  of 
Animal  Industry).  It  may  be  bought  of  Dairy  Machinery  and 
Construction  Co.,  Shelton,  Conn. 

In  Fig.  24  it  is  shown  how  the  cooler  of  this  apparatus  is 
placed  in  the  weigh  room  and  the  filler  in  the  milk  room. 

Hot  Water. — Hot  water  may  be  readily  obtained  at  compara- 
tively small  expense  from  a  tank,  such  as  is  commonly  employed 


HANDLING  OF  MILK  AND  CREAM 


for  supplying  households  with  hot  water  when  attached  to  the 
kitchen  stove,  by  connecting  the  tank  with  a  coil  of  pipe  placed  in 
an  ordinary  air-tight,  wood  stove.     If  a  steam  boiler  is  in  use,  the 

Fig.  24. 


<^^^^^^^feW^J^^^^^^" 


An  arrangement  of  cooler  and  hand  bottle  filler. 
Industry,  Bull.  104.) 


(Bureau  of  Animal 


steam  may  be  run  into  a  tank  of  cold  water.  The  steam  heating- 
tee  is  a  most  convenient  appliance  for  heating  water  (see  p.  131). 
In  either  case  the  stove  or  boiler  should  be  placed  in  an  adjoining 
room,  to  avoid  dirt,  while  the  tank  is  in  the  milk  room. 


122 


CLEAN  MILK 


Cleaning  Utensils. — After  milking,  all  the  utensils,  including 
milk  pails,  receiving  tank,  cooler,  straining  cloths,  etc.,  should  be 
at  once  rinsed  in  cold  water,  then  washed  in  hot  water  and. 
washing  soda  (sodium  carbonate  in  3  per  cent,  solution),  and 
rinsed  again  in  clean,  cold  water.  Finally,  all  metal  dairy  uten- 
sils should  have  boiling  water  poured  over  them,  which  steri- 
lizes and  dries  them  at  once.  Seamless  utensils  are  always  pre- 
ferable, as  offering  no  crevice  for  germs  to  lodge.  Dairy  utensils 
should  never  be  dried  with  towels.  The  cans  should  be  scalded 
■with  boiling  water  or  have  live  steam  turned  in  them  and  be  placed 
upside  down  on  bars  to  drain  in  the  milk  room,  thus  also  admitting 
air.     Rusty  cans  should  never  be  used;  they  sometimes  impart  a 

Fig.  25. 


Wash  Sink. 

fishy  taste  to  milk.  A  fishy  flavor  is  said  to  be  given  to  milk  and 
butter  when  washing  powder  is  not  well  rinsed  from  dairy  utensils, 
also  by  cows  drinking  stagnant  water. 

Square  cans  have  been  recommended  on  account  of  the  con- 
venience and  economy  in  stowing  them  during  transportation  in 
wagons  and  cars.  The  wooden  stopper,  which  is  used  for  milk 
cans  in  some  places,  is  undesirable,  as  it  is  much  more  difficult  to 
sterilize  than  the  tin  stopper.  When  milk  cans  become  much  bat- 
tered and  dented  they  are  also  difficult  to  keep  clean  and  should  not 
be  used  in  that  condition. 

A  convenient  arrangement,  when  steam  is  employed,  is  the 
wash  sink  (see  Fig.  25),  provided  with  draining  trays  at  each  end. 


HANDLING  OF  MILK  AND  CREAM 


123 


The  can  is  placed  upside  down  over  the  two  nipples  in  the  tray,  one 
supplying  a  jet  of  water  to  rinse  the  can,  and  the  other  a  jet  of 
steam  to  sterilize  or  kill  germs  in  it.  Various  forms  of  brushes  are- 
desirable  for  scrubbing  the  utensils  (see  Fig.  26).  They  should 
be  boiled  daily  for  ten  minutes  after  use. 

To  keep  milk  cool  in  cans  during  shipment  the  refrigerator 
car  is  commonly  employed.  Where  this  is  not  possible,  the  writer 
recommends  the  use  of  a  cylindrical,  hollow  can  of  tin,  with  open 
top  and  closed  bottom,  being  suspended  bottom  down,  well  into  the 
milk  or  cream,  from  the  mouth  of  the  shipping  can,  and  filled  with 
cracked  ice.     The  milk  can  jacket,  made  of  hair,  felt  and  canvas, 

Fig.  26. 


wimmr 


Various  Forms  of  Brushes. 

will  protect  cans  against  the  effect  of  heat  and  cold  to  a  considerable 
extent  (see  Fig.  27).  Cans  may  be  kept  cool — while  waiting  for 
the  train  at  a  station — by  placing  a  cake  of  ice  on  a  stand  raised 
three  feet  above  the  ground,  and  by  stowing  the  cans  about  this  and 
covering  the  whole  with  canvas  reaching  to  the  ground. 

Bottled  Milk. — If  milk  is  to  be  shipped  in  bottles  instead  of 
cans,  the  following  utensils  will  be  essential  in  the  milk  room : 


Glass  bottles,  made  to  withstand  heat,  and  delivery  boxes. 

A   receiving  tank,  with  trap  strainer. 

A  cooler,  with  ice-water  section. 

A  collecting  tank. 

A  bottle-filler,  with  table. 

A  sterilizer. 

A  washing  outfit. 


I24 


CLEAN  MILK 


The  cooling  arrangement  is  precisely  as  described  above  for 
cooling  milk  to  be  shipped  in  cans.  When  there  are  eight  or  ten 
milkers,  so  that  the  milk  from  as  many  cows  may  be  mixed  as  soon 
as  milked  without  loss  of  valuable  time  when  it  should  be  cooling, 
then  the  warm,  mixed  milk  may  properly  be  drawn  directly  into  the 
bottles  from  the  bottle  filler.  The  bottles  should,  on  being  filled,  be 
instantly  immersed  to  the  neck  in  ice  water.  In  this  way  bottled 
milk  may  be  suitably  cooled,  with  the  avoidance  of  the  unnecessary 
exposure  to  two  tanks  and  the  air  in  passing  over  the  cooler.  The 
bottle  filler  is  indispensable  (see  Fig.  28)  for  conveniently  filling 
several  bottles  at  once.    By  moving  a  lever  one  can  fill  from  four  to 

Fig.  27. 


Milk  Can  Jacket. 


eighteen  bottles  to  the  same  level  at  one  time.  The  prices  of  these 
contrivances  vary  greatly  with  the  size  and  material  used  in  their 
construction. 

The  sterilizer  is  an  important  utensil.  It  is  a  tight  chamber 
into  which  steam  is  turned,  with  the  object  of  destroying  germs,  and 
is  made  to  hold  the  bottles  and  absolutely  every  other  dairy  utensil 
with  which  milk  comes  in  contact. 

The  germs  are  not  only  those  which  may  have  inhabited  the 
milk,  but  occasionally  there  may  be  germs  of  disease  contaminating 
the  returned  bottle,  owing  to  it  having  been  in  a  house  in  which 
such  disease  existed. 


HANDLING  OF  MILK  AND  CREAM 


12  = 


There  are  two  styles  of  steam  sterilizers — those  in  which  the 
steam  is  not  under  pressure,  and  those  confining  steam  under 
pressure. 

The  latter  type  is  more  efficient,  in  that  with  steam  under 
pressure  it  is  possible  to  obtain  a  much  higher  temperature  than 
when  it  is  not.  Steam,  when  not  under  pressure,  will  not  exceed  in 
temperature  boiling  water    (2120   R).     With  a  pressure  of  ten. 

Fig.  28. 


XI — ^ 


Star  Side-Bar  Filler. 


pounds  and  a  temperature  of  241  °  F.  in  the  high  pressure  sterilizers, 
it  is  possible  to  destroy  the  germs  in  the  milk  utensils  with  as  much 
certainty  in  twenty  minutes  as  with  steam  at  2120  F.  in  the  low 
pressure  sterilizers  in  an  hour.  The  heavy  pressure  or  high  pressure 
sterilizers  are,  however,  exceedingly  expensive,  and,  if  the  bottles 
are  properly  washed,  there  is  practically  no  danger  in  relying  upon 
the  less  expensive  steam  sterilizers  in  which  the  steam  is  not  con- 


126 


CLEAN  MILK 


fined  under  pressure.  In  Fig.  29  is  shown  a  high  pressure  steri- 
lizer. It  must  be  built  very  strongly  to  withstand  the  pressure, 
which  is  over  fifteen  tons  against  the  door  alone,  with  a  pressure  of 
ten  pounds  of  steam  in  the  sterilizer.    The  matter  of  a  sterilizer  in 


Fig.  29. 


Star  High  Pressure  Sterilizer. 


which  the  steam  is  not  confined  under  pressure  is  a  comparatively 
simple  affair.  One  may  be  home-made.  The  writer  had  a  sterilizer 
built  of  two-inch  plank,  lined  with  galvanized  iron,  with  double 
doors  fastened  with  an  iron  bar  across  the  front.     The  shape  was 


HANDLING  OF  MILK  AND  CREAM  127 

nearly  square  and  the  capacity  was  about  250  quart  bottles.  There 
was  a  movable  sheet  of  galvanized  iron,  partitioning  the  sterilizer 
in  two,  and  movable  shelves  of  the  same,  perforated  with  holes,  in 
which  the  bottles  rested  upside  down  on  their  shoulders.  The 
shelves  stretched  horizontally  across  the  sterilizer,  from  each  side 
to  the  partition  in  the  centre,  resting  on  galvanized  angle  irons 
soldered  along  both  sides  and  on  each  side  of  the  partition  in  the 
centre.  The  shelves  were  just  far  enough  apart  to  give  room  for  a 
tier  of  bottles.  Shelves  and  partition  were  removed  to  allow  of 
room  for  sterilizing  the  milk  pails,  cooler,  bottle  filler  and  strainer, 
cheesecloths,  and  tanks  supplying  and  receiving  milk  from  cooler, 
etc.  The  sterilizer  was  fed  from  a  ten  horse  power  boiler  with 
steam  from  below,  and  also  had  an  exit  or  exhaust  in  the  bottom, 
while  at  the  top  there  was  a  hole  in  which  was  a  cork  holding  a 
thermometer  in  place,  with  bulb  inside  and  recording  part  outside  of 
sterilizer.  The  doors  were  not  steam-tight,  and  no  pressure  of 
steam  was  attempted  or  possible  in  the  sterilizer,  but  the  tempera- 
ture was  raised  2120  in  about  twenty  minutes,  and  maintained  for 
the  time — one  hour — occupied  by  sterilization. 

A  very  successful  sterilizer  has  recently  been  made  by  my 
friend,  Hon.  W.  H.  Paulhamus,  of  Sumner,  Wash.,  entirely  of  con- 
crete faced  with  cement,  and  costing  about  $75.00.  It  is  a  rectangu- 
lar chamber  6l/2  feet  high  by  8  feet  wide  and  about  14  feet  long- 
and  6  inches  thick,  with  one  iron  door.  In  the  top,  iron  bars  were 
used  to  reinforce  the  concrete.  Two  half-inch  pipes  enter  one  side 
of  the  chamber  just  above  the  floor  for  intake  of  steam  from  a 
twenty-five  horse  power  boiler,  and,  at  the  top,  there  is  a  single 
pipe  for  outlet  of  steam  when  sterilization  is  over  to  cool  off  the 
oven,  and  one  to  drain  the  floor.  In  the  middle  of  one  side  there  is 
also  a  pipe  inserted,  large  enough  to  hold  a  thermometer.  This 
sterilizer  will  hold  100  dozen  bottles  and  every  bit  of  dairy  appar- 
atus used  on  four  farms,  including  the  milk  pails  and  milk  cans, 
coolers,  and  bottle  filling  apparatus,   strainer  cloths,  etc.     If  one 


128 


CLEAN  MILK 


does  not  wish  to  make  a  sterilizer,  the  largest  size  only  should 
be  bought  (Fig.  30),  as  it  is  most  economical  in  saving  the 
expense  of  doing  several  sterilizations  daily,  because  with  it  all 
bottles  and  every  article  of  dairy  utensil  can  be  sterilized  at  one 
time.  In  case  the  Star  galvanized  sterilizer  is  used,  the  bottle 
carriers  described  on  page  137  may  be  employed  to  hold  the  bottles 
in  the  sterilizer,  or  a  rack  and  truck  similar  to  that  pictured  on  pages 
103  and  104  may  be  utilized. 

Fig-  30. 


"■"ilSfHi'S"    '■■■■    .■ 


Star  Sterilizer. 


This  sterilizer  is  made  of  heavy  galvanized  iron,  riveted  and 
soldered  together,  and  holding  from  240  to  632  quart  bottles,  ac- 
cording to  the  size.  It  is  supplied  with  perforated  steam  coil  and 
trapped  drain  outlet,  and  it  is  well  to  have  an  exhaust  to  carry  off 
surplus  steam,  although  the  doors  are  not  steam-tight  when  closed. 
A  thermometer  placed  in  the  centre  of  the  door  is  also  advisable. 
Both  the  heavy  pressure  and  the  galvanized  iron  sterilizers  are 
made  either  with  a  door  at  one  end  or  a  door  at  each  end.  The 
latter  arrangement  is  a  convenience  when  there  is  a  separate  room 


HANDLING  OF  MILK  AND  CREAM 


129 


for  washing  the  bottles,  the  sterilizer  being  placed  in  the  partition 
between  the  washing  and  bottling  room  and  the  bottles  passed  in 
the  sterilizer  through  a  door  in  the  wash  room  and  taken  out 
through  the  other  door  in  the  sterilizer  in  the  bottling  room.  Every 
single  utensil  with  which  milk  comes  in  contact,  including  the 
various  tanks  and  strainer  cloths,   should  be  thoroughly   washed 

Fig-  31- 


Bottle   Brush. 

and  sterilized  after  each  milking  for  one  hour  at  2120  F.  To  avoid 
sterilization  twice  daily,  however,  it  is  better  to  have  two  sets  of 
utensils,  which  may  be  sterilized  all  together  once  daily. 

Washing  Outfit. — A  separate  room  should  be  provided  for 
washing  milk  utensils  where  the  best  plan  is  pursued.  Since  we 
are  considering  the  essentials  for  handling  clean  milk  we  have  not 
included  a  wash  room  separate  from  the  milk  room,  as  clean  milk 


Star    Metal   Wash    Sink. 


can  be  handled  in  a  combination  bottling-  and  wash  room,  although 
not  to  the  best  advantage.  The  bottles  should  be  rinsed  in  warm 
water  and  washed  with  washing  soda  and  hot  water  (in  3  per  cent. 
solution)  with  a  bottle  brush  (see  Fig.  31 ),  and  then  rinsed  in  clean 
hot  water  and  inverted  over  the  trays  or  shelves,  which  are  placed 
in  the  sterilizer.  The  most  convenient  arrangement  is  such  as  that 
shown  in  the  cut  (Fig.  t,-),  two  tanks,  one  holding  lukewarm  water 


130 


CLEAN  MILK 


in  which  the  bottles  are  soaked,  and  the  other  hot  water  containing 
washing  soda,  while  at  the  end  there  are  projecting  nipples  over 
which  the  bottles  are  inverted,  and,  by  turning  the  lever,  several 
bottles  are  rinsed  at  once.  Each  tank  has  an  overflow  standpipe  to 
carry  off  the  grease  floating  on  the  top  of  the  water. 

An  additional  improvement  is  the  turbine  bottle  washer  shown 
in  the  illustration  (Fig.  33).  It  consists  of  a  revolving  brush  which 
is  turned  by  a  turbine  wheel  with  steam  at  a  pressure  of  twelve  to 
fifteen  pounds.     In  this  cut  are  shown  the  two  large  tanks  on  the 

Fig-  33- 


Star  Bottle  Washing  Outfit. 


left,  for  soaking  and  washing  bottles  in  washing  soda  and  water, 
and  then  the  small  tank,  next  the  bottle  washer,  over  which  the 
bottles  are  inverted  to  be  rinsed  inside.  This  is  accomplished  by 
nipples,  as  shown  in  the  cut  (Fig.  32),  spraying  water  into  the  in- 
terior of  a  number  of  bottles  at  one  time,  which  are  then  dipped  in 
the  small  tank  below  to  wash  the  outside  of  the  bottle,  and  are 
transferred  to  the  tank  at  the  extreme  right  to  drain. 

None  of  this  special  bottle-washing  outfit  is  essential.  Any 
convenient  arrangement  of  tubs  and  hot  water  by  which  the  bottles 
are  put  through  three  processes  in  washing — first  rinsing  in  warm 


HANDLING  OF  MILK  AND  CREAM  131 

water,  then  in  hot  alkali  and  water,  and  finally  in  clean  hot  water — 
will  suffice. 

If  the  bottles  are  thoroughly  rinsed  at  the  consumer's  house 
the  first  rinsing  in  plain  water  may  even  be  dispensed  with,  pro- 
vided  the  bottles   are   thoroughly   scrubbed   inside  Fig.  34. 
with  a  brush  and  hot  alkali  water  and  well  rinsed 
in  clean  hot  water.     The  hot  water  may  be  sup- 
plied from  a  hot  water  tank,  as  suggested  (p.  120), 
or  by  means  of  a  steam  heating  tee    (Fig.   34).     Stea~Heating. 

This  is  an  arrangement  by  which  water  may  Tee. 

be  heated  to  almost  any  temperature  desired  (short  of  boiling), 
by  steam  and  cold  water  coming  in  contact,  in  varying  proportions, 
according  to  the  amount  of  either  which  is  permitted  to  flow  into- 
the  tee.  Thus  the  steam  enters  the  side  and  the  water  the  top  of 
the  tee,  both  being  regulated  by  valves  in  the  steam  and  water  pipes, 
and  the  hot  water  flows  out  below.  Cold  water  or  steam  may  be: 
obtained  separately  also,  from  the  device,  which  is  comparatively' 
inexpensive.  A  very  convenient  bottle-washing  machine  is  shown 
in  the  Appendix  (p.  328). 

The  routine  of  operating  the  dairy  would  be  as  follows :  The 
empty,  returned  bottles  would  be  taken  from  the  wagon  boxes  into 
the  milk  room  and  there  rinsed  in  warm  water,  in  one  tub,  and  then 
scrubbed  with  a  brush  in  another  tub  holding  alkali  and  water,  as 
hot  as  the  hand  can  bear.  The  bottles  should  be  next  rinsed  in 
clean,  hot  water,  inverted  in  the  racks  and  placed  in  the  sterilizer, 
where  they  are  sterilized  at  21 2°  F.  (as  shown  by  a  reliable  ther- 
mometer) (Fig.  35)  for  an  hour.  The  bottles  should  remain  in- 
verted until  used. 

The  milk  is  brought  from  the  barn  in  milk  pails  or  cans,  as 
soon  as  milked,  and  poured  into  the  Star  trap  strainer  resting  in 
the  receiving  tank  of  the  Star  milk  cooler  with  ice  water  section, 
or,  better,  into  the  covered  cooler  described  on  p.  119).  The  milk 
flows  from  the  collecting  tank  of  the  cooler  into  a  large  can,  if 


132  CLEAN  MILK 

it  is  desired  to  thoroughly  mix  the  milk  of  many  cows  before 
it  is  bottled.  Instead  of  a  can  for  mixing  the  cooled  milk,  it  is 
better  to  use  the  large  tank  for  filling  the  bottles — that  is,  the  bottle- 
filler  tank;  and  after  twenty  gallons  or  more  of  milk  have  flowed 
from  the  collecting-tank  of  the  cooler  into  the  bottle-filler  tank,  the 
milk  should  be  well  stirred  with  a  sterilized  stirrer  and  the  bottles 
filled  while  the  milk  is  being  mixed.  The  stirrer  may  be  made  like 
a  huge  fork,  from  heavy  tin. 

The  warm  milk  of  several  cows  may  be  mixed  in  the  barn  by- 
pouring  the  contents  of  a  number  of  milk  pails  into  a  large  can. 
But  unless  there  are  enough  milkers  to  do  this  within  a  few  min- 
utes, it  is  better  to  carry  each  milk  pail  to  the  cooler,  as  soon  as  it 
is  full  and  mix  the  milk  after  it  has  cooled.  The  time  elapsing 
between  milking  and  bottling  should  be  as  short  as  possible.     The 


milk  must  be  cooled  instantly  after  milking,  and  be  bottled  within 
an  hour  of  milking.  In  some  establishments  the  milk  is  bottled 
within  eight  minutes  of  milking.  The  cooled,  mixed  milk  is  poured 
into  the  bottle  filler  and  flows  immediately  into  the  bottles,  which 
are  then  quickly  capped  with  sterilized  paper  caps,  and  placed  in  the 
wagon  boxes  well  surrounded  with  ice  in  warm  weather.  Milk 
bottles  should  always  be  cool  before  they  are  filled  with  milk.  This 
is  especially  true  of  the  smaller  sizes,  which  it  is  wise  to  keep  in  cold 
storage  an  hour  before  filling.  The  milk  should  be  delivered  to  the 
consumer  the  year  round  at  a  temperature  not  over  45 °  F.  If  not 
shipped  immediately — as  in  case  of  the  night's  milk — the  milk  may 
be  stored  in  the  wagon  boxes  over  night  with  ice  or  kept  in  cold 
storage  or  in  sufficiently  cold  water.     (Fig.  36). 

All  the  dairy  utensils  should  be  rinsed  in  clean  warm  or  cold 
Water  as  soon  as  the  milk  has  been  bottled  and  then  washed  with 


HANDLING  OF  MILK  AND  CREAM  133 

scalding  alkali  water  and  rinsed  with  clean  cold  water,  and  steril- 
ized an  hour  in  the  sterilizer,  including  the  cheesecloth  used  in 
straining  the  milk  in  the  milk  pails  and  in  the  Star  trap  strainer. 
It  is  safer  to  use  new,  fresh,  sterile  cheesecloth  at  each  milking.  The 
floor  must  be  kept  damp  to  avoid  dust,  and  the  windows  and  doors 
should  be  closed  while  the  milk  is  being  handled  for  the  same 
reason.  When  dairy  utensils  are  not  in  use,  they  may  be  kept  in 
a  sterilizer,  or,  if  this  is  not  practicable,  it  is  well  in  many  milk: 
rooms  to  cover  them  with  a  clean  sheet,  to  keep  off  the  dust,  and  to 
rinse  the  cooler  with  clean,  cold  water  just  before  using,  for  the 
.same  reason;  or,  better,  to  use  a  covered  cooler.  A  properly  con- 
Fig.  36. 


Machine   for  chopping  ice  used  to  pack  about  milk  bottles. 


structed  and  managed  milk  room  should  be  dust-proof  and  dust-free, 
and  such  precautions  should  be  entirely  unnecessary. 

Turning  live  steam  against  the  walls  of  the  milk  room  each 
day  is  useful  as  an  aid  to  cleanliness,  provided  that  they  are  con- 
structed to  withstand  the  process. 

The  employees  in  the  milk  room  ought  to  wear  clean,  washable 
caps  and  clothes.  Linen  gowns,  like  those  worn  by  butchers,  which 
may  be  slipped  over  the  clothes,  are  most  convenient. 

The  final  test  of  perfection  of  cleanliness  of  the  milk,  pro- 
duced as  described,  is  the  laboratory.     Such  tests  should  be  made 


134 


CLEAN  MILK 


once  a  week.  If  the  milk  is  sold  as  "  certified,"  it  must  receive 
the  sanction  of  some  medical  milk  commission  or  Board  of 
Health.  The  bacterial  content  or  number  of  germs  should  not  ex- 
ceed 30,000.  10,000  germs  is  the  maximum  number  permitted  by- 
many  milk  commissions  (see  p.  25)  to  the  cubic  centimeter,  and  this 


Fig-  37- 


Banjo   Conductor   for   carrying   milk   through    a  wall. 

is  the  proper  standard  according  to  the  consensus  of  authorities  at 
the  present  time,  in  so-called  certified  milk.  It  is  perfectly  possible 
to  produce  milk  which  shall  not  exceed  in  number  2,000  to  4,000 
germs  to  the  cubic  centimeter  by  the  comparatively  simple  and  inex- 
pensive plant  which  has  just  been  described  above,  as  the  author 
has  practically  demonstrated. 

Fig-  33. 


'  ■   w 


Cylinder  for  conveying   milk   through   a   floor. 


A  more  perfect  arrangement  in  a  dairy  building  for  handling- 
clean  milk  is  of  advantage  when  one  can  afford  it.  The  most  im- 
portant improvement  consists  in  separating  the  bottling  or  milk 
room  proper  from  the  wash  room,  in  which  the  sterilization  and 
washing  of  the  milk  utensils  are  done,  and  to  devote  two  rooms  to 
these  different  processes.     ( 1 )  The  boiler  and  engine  should  have  a. 


HANDLING  OF  MILK  AND  CREAM 


135 


separate  room,  and  adjoining  this  (2)  a  room  for  washing  and 
sterilization,  and  then  a  room  (3)  in  which  the  milk  is  cooled  and 
bottled.  A  still  further  development  comprises  the  following  in  the 
dairy  building: 


A  Milk  Receiving  Room. 
A  Milk  Room. 
A   Bottle   Room. 
A   Wash    Room. 
An  Engine  Room. 


A  Boiler  Room. 

A  Cold  Storage  Room. 

A  Shipping   Room. 

A   Lavatory. 

A   Laundry. 


Fig-  39- 


Cream  Cooler  connected  with   Separator. 


The  milk  receiving  room  may  be  connected  with  the  barn  by 
a.  cable  system  by  which  two  5  to  10  gallon  cans  are  suspended  on 
can  carriages  running  on  an  overhead  wire.  The  milk  receiving 
room  is  on  a  higher  level  than  the  milk  room,  so  that  the  milk 
flows  from  it  through  the  floor  through  a  funnel  or  cylinder,  or 
through  the  wall  by  a  Banjo  conductor  (see  Figs.  37  and  38)  di- 


136 


CLEAN  MILK 


rectly  into  the  receiving  tanks  of  the  cooler  or  separator  in  the  millc 
room  below,  thus  avoiding  unnecessary  handling. 

The  milk  room  should  not  be  connected  with  the  outer  air  by 
a  door  or  open  window,  but  must  be  ventilated  so  as  to  exclude 
dust  and  only  be  connected  with  the  other  rooms.  It  contains  the 
appliances  for  cooling  and  bottling  milk  we  have  already  noticed, 
and  also  a  separator,  cream  cooler  and  cream  bottle  filler  (Figs.  39 
and  40),  if  cream  is  to  be  made. 

The  bottle  room  adjoins  the  milk  room,  in  which  the  clean 
bottles  are  kept  after  being  sterilized.     One  end  of  the  sterilizer 

Fig.  40. 


-Mm 


Cream  Bottle  Filler. 


projects  into  this  room  from  the  wash  room.  The  wash  room  con- 
tains the  sterilizer,  the  bottle  washing  outfit,  and  a  Babcock  tester. 
The  cold  storage  room  is  of  great  convenience  where  large  quanti- 
ties of  milk  are  handled  and  may  be  arranged  with  natural  ice,  or 
by  means  of  ammonia  compression  and  an  artificial  refrigerating 
and  ice-making  plant.  The  lavatory  and  laundry  are  for  the  use 
of  the  employees  in  the  dairy,  the  former  with  a  shower  bath,  set 
basin  and  dressing  room,  and  the  latter  to  wash  the  clothes  used  by 
the  employees.  In  the  shipping  room  are  the  cases  for  holding 
the  bottles,  and  the  floor  platform  for  loading  the  wagons  should 
be  on  a  level  with  them.     Where  there  is  machinery,  as  for  a  re- 


HANDLING  OF  MILK  AND  CREAM 


17 


f  rigerating  plant,  it  is  well  to  separate  the  boiler  by  a  partition  from 
the  engine  and  fire  room  and  thus  avoid  the  dust,  ashes  and  dirt 
from  fuel.* 

Space  does  not  permit  of  more  than  a  brief  outline  of  the  more 
elaborate  dairy  plant,  but  we  would  refer  to  onef  who  makes  a 
"business  of  planning  and  installing  such,  from  whom  we  have  de- 
rived many  valuable  suggestions.  The  object  of  this  book  is  to 
detail  the  less  elaborate  and  more  essential  methods  which  may  be 
used  by  the  farmer  without  great  expense  in  the  production  of 
clean  milk  on  a  moderate  scale. 

Fig.  41. 


COPYRIGHT,  1908, 


Bottle  Carriers. 

In  the  handling  of  milk  bottles  in  the  dairy,  it  is  much  more 
convenient— though  not  essential— if  they  can  be  transported  and 
inverted  in  numbers  without  handling  each  bottle  separately.  Thus 
carriers  have  been  invented  for  holding  them,  with  reversing  racks, 
so  that  the  bottles  may  be  inverted— as  when  they  are  washed  and 
sterilized— by  turning  over  as  many  as  20  bottles  at  once  (see  Fig. 
41 ).     Cars  are  also  made  which  are  used  to  transport  these  carriers 


*  For  plan  of  milk  house,  see  p.  324"36- 
t  Samuel  M.  Heulings,  Haddonfield,  N-  J. 


138 


CLEAN  MILK 


and  the  cars,  carriers  and  bottles  are  all  wheeled  directly  into  the 
sterilizer  and  out  again  without  handling  the  individual  bottles 
(see  Figs.  41  and  42). 

Shipping  Cases  and  Boxes. — Milk  bottles  of  glass  must  be 
shipped  in  some  sort  of  box.  The  writer  has  had  such  boxes  made 
of  strong  galvanized  iron  (24  gage)  with  rolled  edges  at  all  the 
joints,  with  a  hinged  cover  and  padlock,  and  with  metal  handles 
at  either  end.  Padlocks  must  be  made  to  have  the  same  key  fit 
them  all;  but  we  have  found  great  trouble  in  getting  padlocks  which 


Fig.  42. 


A    Car    for    conveying    carriers    and   bottles. 


were  not  continually  getting  out  of  order.  For  this  reason,  and 
because  keys  for  such  padlocks  are  readily  obtained  by  outsiders, 
I  recommend  the  use  of  a  lead  seal  having  an  opening  through 
which  the  ends  of  short  wires  are  passed.  The  seal  is  then  com- 
pressed by  a  special  punch,  thus  locking  the  ends  of  the  wires  and 
serving  as  a  perfect  padlock  which  is  not  likely  to  be  tampered 
with  without  detection.  The  seal  and  wire  for  each  shipping 
box  cost  about  one-sixth  of  a  cent  and  may  be  obtained  complete 
with   the  punch.      One   called   "  The   Enterprize   Punch   &   Seal  '* 


HANDLING  GF  MILK  AND  CREAM 


139 


bis  proved  efficient.  The  boxes  hold  12  quart  bottles,  which  are 
separated  by  a  framework  of  galvanized  iron  on  the  same  plan  as 
the  pasteboard  partitions  or  fillers  in  egg  cases.     These  frames  lift 

Fig-  43- 


A  Car  for  conveying  carriers  and  bottles. 

out  of  the  boxes  and  are  3^  inches  deep.  The  boxes  are 
123/2  X  17^  X  10  inches  deep  and  have  a  small  hole  punched  in. 
the  bottom  to  allow  the  water,  from  melting  ice,  to  drain  away. 
This  is  advisable  in  saving  ice  and  the  weight  of  the  water  in 

Fig.  44. 


COPYRIGHT 

Wagon  Box  for  carrying  bottles  and  ice,  not  covered  or  locked. 

transportation.  I  have  found  the  locked  boxes  necessary  to  pre- 
vent theft  of  the  milk  and  empty  bottles  in  transportation.  Boxes 
may  be  bought  holding  various  quantities  of  bottles,  as  20  or  14 
pints  (see  Fig.  44).     (For  Bottle  caps,  see  p.   168.) 


140 


CLEAN  MILK 


Bottles. — In  regard  to  glass  bottles  there  is  not  much  to  say 
except  that  a  bottle  of  good  material  and  proper  annealing  must  be 
secured  to  stand  the  repeated  sterilizations  (Fig.  45).  The  shapes 
are  more  a  matter  of  taste  than  anything  else.  The  bottles  with 
the  long  and  slender  necks  make  a  greater  display  of  cream.  The 
latest  departure  in  the  way  of  a  milk  bottle  is  the  single  service 
milk  container  of  wood-paper  made  and  invented  by  G.  VV.  Max- 
well of  2101  Folsom  St.,  San  Francisco.  It  is  now  in  actual  use 
by  dairymen  in  Los  Angelos,  Cal.  The  containers  in  shape  re- 
semble an  ordinary  drinking  glass.     There  are  quart,  34  >  %  and 

Fig-  45- 


Milk  Bottles. 

pint,  sizes.  The  pints  are  $y2  in.  high  and  3  in.  across  the  top. 
The  quarts  are  6)/2  in.  high.  The  pints  weigh  1  ounce;  the  quart 
sizes.  2  ounces.  After  the  containers  are  filled  with  milk  the  paper 
cover  is  pressed  down  firmly  into  the  narrowing  container,  until  it 
becomes  securely  wedged  in  place,  and  is  held  there  by  four  small 
tongues  punched  from  the  walls  of  the  container  (which  press  upon 
the  top  of  the  paper  cover  and  are  *4  m-  from  the  top  rim  of  the 
container)  by  the  bottle  filling  and  capping  machine  (Fig.  46).  Af- 
ter the  containers  are  made  they  are  dipped  into  melted  paraffin  at 
2200  F.,  which  ensures  absolute  sterility  and  water-tightness.  The 
containers  and  covers  are  nested  and  packed  in  sterile  paper  in 


Fig.  46. 


Maxwell  Paper  Bottle  Filling  and  Capping  Machine. 


HANDLING  OF  MILK  AND  CREAM  141: 

wooden  boxes  and  in  no  part  of  the  making  or  handling  do  either 
come  in  contact  with  the  hands  or  other  contaminating  objects.  Ad- 
ditional caps  (to  take  the  place  of  parchment  paper  caps  on  glass 
bottles)  are  supplied  for  certified  milk  to  keep  the  dust  from  the 
inside  covers  of  the  bottles.  An  ingenious  metal  opener  is  pro- 
vided consumers  wherewith  the  covers  are  removed  without  danger 
of  their  falling  sidewise  into  the  container.  A  special  machine 
(some  of  which  are  very  cheap)  is  made  for  filling  and  capping 
the  bottles  so  that  the  containers  and  covers  are  not  touched  by 
the  hands.  The  paper  bottles  are  several  inches  shorter  than  the 
glass  bottles,  on  account  of  their  thinner  walls;  the  paper  lids  fit 
down  into  the  bottle  and  allow  of  no  leaking;  and  the  necks  are 
wide  enough  to  remove  the  cream  with  a  spoon.  The  cost  is  about 
0.7  of  a  cent  each  for  a  quart,  and  0.5  of  a  cent  for  pint  paper  con- 
tainers. The  paper  container  is  first  of  all  of  most  value  because  it  is 
absolutely  free  from  germs,  i.  c,  sterile.  Then  it  does  away  with 
breakage,  and  with  loss  of  glass  bottles  from  various  causes.  Again, 
the  paper  bottle  does  away  with  the  cleaning  and  sterilization  re- 
quired by  glass  bottles.  And,  moreover,  there  is  saving  in  weight 
in  transportation  of  paper  bottles.  The  latter  weigh  2  ounces 
against  the  26  ounce  glass  quart  bottle.  A  city  dealer  selling  3,000 
qts.  of  bottled  milk  daily  might  save  some  $60.00  monthly  in  loss 
of  glass  bottles,  and  as  much  more  required  for  labor  and  power, 
by  the  use  of  paper  bottles.  But  the  paper  bottles  would  cost  some 
$612.00  per  month. 

And,  while  there  is  so  much  saving  in  weight  that  almost  twice 
as  much  milk  could  be  carried  on  wagons  in  paper  bottles,  yet  this 
is  of  little  advantage,  as  it  is  now  possible  to  carry  as  many  glass 
bottles  on  a  wagon  as  one  man  can  distribute  (300)  in  a  day.  There 
would  be  some  saving  of  the  milkman's  time  because  he  would  not 
collect  empty  bottles.  The  only  disadvantage  which  occurs  to  the 
writer  is  the  fact  that  quality  and  quantity  of  the  cream  would  not 
be  so  apparent  in  the  paper  bottles,  nor  would  dirt. 


1 42  CLEAN  MILK 

The  consumer  is  benefited  in  the  great  safety  of  the  sterile 
containers  in  place  of  the  often  dirty  milk  bottle  which  may  have 
just  been  used  by  a  patient  suffering  from  some  contagious  dis- 
ease. 

From  a  sanitary  point  of  view  the  single-service,  sterile,  paper 
milk  container  is  immeasurably  superior  to  the  (commonly)  im- 
perfectly clean  glass  bottle,  and,  from  this  point  of  view,  its  extra 
expense  should  not  be  considered.  The  advent  of  the  paper  con- 
tainer, while  entailing  some  extra  expense  to  the  city  bottler  of  milk, 
should  be  of  enormous  advantage  in  enabling  farmers  to  ship 
milk  in  bottles  at  lower  freight  rates  (on  account  of  less  weight 
and  bulk  of  paper  containers)  and  without  all  the  expense  of  ma- 
chinery and  labor  now  required  in  washing  and  sterilizing  glass 
bottles. 

The  same  care  should  be  exercised  in  the  production  of  cream 
as  in  the  case  of  milk.  While  99  per  cent,  of  germs  in  milk  are  to 
be  found  in  the  cream  which  rises  naturally  on  that  milk,  separated 
cream  contains  about  one-fourth  of  the  germs  in  the  milk  from 
which  it  is  obtained.  But  as  the  cream  constitutes  only  a  small  part 
of  the  original  milk — say  one-sixth — the  actual  number  of  germs 
in  a  given  amount  of  separation-cream  would  be  greater  than  in 
the  same  quantity  of  the  milk  from  which  the  cream  was  separated. 

Cream  in  cities  is  consumed  largely  on  the  table  and  for  mak- 
ing ice  cream  and  whipped  cream.  Fatal  poisoning  has  occurred 
from  ice  cream  made  from  unclean  milk  (see  p.  38).  Babies  are 
chiefly  fed  nowadays  on  cream  and  water.  The  cream  is  usually 
removed  from  milk  at  the  infant's  home,  but  market  cream  is  often 
used  for  this  purpose.* 

When  cream  is  used  for  any  of  the  purposes  recited,  it  is  im- 
perative that  the  cream  should  be  clean  or  as  free  from  germs  as 
possible.  We  have  already  alluded  to  the  value  of  clean  cream  for 
butter-making. 

The  warm  milk  direct   from  the   cow  must  be   immediately 

*  The  composition  of  proteids  is  altered  by  separation  of  cream  by  centrifugal 
action.  Thus  albumoses  and  peptones  from  averaging  9.69  £  of  proteids  in  fresh 
milk  are  increased  to  18  to  38^'  in  separator  cream.  Gravity  cream  is  thought 
better  for  infant  feeding. 


HANDLING  OF  MILK  AND  CREAM 


M3 


separated,  as  a  temperature  of  86°  F.  is  most  favorable  for  separa- 
tion. Nor  must  time  be  permitted  for  germs  to  multiply  in  the 
warm  milk  between  milking  and  separation ;  the  milk  must  be  separ- 
ated as  fast  as  milked.  As  soon  as  the  cream  is  separated  it 
should  be  immediately  cooled  to  below  500  F.,  preferably  to 
400  F.     This  is  best  accomplished  by  allowing  the  cream  to  run 

Fig.  47- 


Hand  Separator  for  separating  cream  from  milk. 


directly  from  the  separator  into  the  receiving  tank  of  a  tubular  or 
Star  cooler.  The  cooler  is  identical  with  that  for  milk,  but  the 
holes  are  larger  in  the  receptacle  which  feeds  the  cooler.  The 
cream  is  transferred  from  the  collecting  tank  of  the  cooler  to  a 
cream  bottle-filler,  and  then  is  run  into  sterilized  bottles.  The 
bottles  are  shipped  like  milk  in  shipping  boxes  and,  except  in  cold 
weather,  are  packed  in  ice.     The  bowl  and  all  movable  parts  of  the 


i44  CLEAN  MILK 

separator  must  be  washed  as  carefully  as  any  other  dairy  utensils 
by  first  rinsing  in  cold  water,  then  scrubbing  in  warm  water  and 
washing  soda  with  a  brush,  and  rinsing  again  with  clean,  cold  water. 
Finally,  the  parts  should  be  sterilized  with  boiling  water  or  by 
placing  them  in  a  sterilizer.  All  this  should  be  done  after  each  use 
of  the  separator.  For  this  reason  a  separator  having  as  simple  con- 
struction and  as  few  parts  which  come  in  contact  with  milk  as 
possible  should  be  preferred.  The  Sharpies  separator  is  one  of  the 
simplest  in  this  respect  and  therefore  most  readily  cleaned.* 

If  the  cream  is  shipped  in  cans,  it  may  be  kept  cool  in  the  same 
manner  as  that  recommended  for  milk  (see  p.  123).  Cream  thick- 
eners of  gelatin  are  not  uncommonly  used  to  thicken  cream.  Starch 
and  syrup  of  lime,  known  as  "  Viscogen,"  are  also  employed. 
Separated  cream  does  not  whip  quite  so  readily  as  set  cream,  and 
syrup  of  lime  may  be  used  to  aid  its  whipping,  without  injury  to 
the  consumer,  provided  that  only  a  small  amount — not  over  one-half 
teaspoonful  of  the  syrup  to  the  pint  of  cream — is  used.  In  fact, 
this  proportion  is  often  employed  in  cream  mixtures  for  feeding 
babies  to  increase  the  digestibility  of  the  cream.  Viscogen  should 
not  be  added  to  cream  for  sale  in  the  market.  For  tests  for  adul- 
terants of  cream,  see  p.  192. 

Cream  of  varying  composition  is  sold  in  the  market.  It  gener- 
ally varies  from  20  to  50  per  cent,  in  fat-content.  Cream  must 
contain  at  least  18  per  cent,  of  fat  according  to  the  U.  S.  Pure 
Food  Law,  June,  1906. 

In  order  that  cream  may  be  readily  whipped,  it  should  contain 
over  20  per  cent,  of  fat  and  be  below  500  F.  in  temperature. 
Cream  containing  23  per  cent,  fat  is  most  economical  for  whipping, 
as  an  excess  of  fat  does  not  aid  the  process.  Cream  should  be  at 
least  24  hours  old — to  contain  a  small  amount  of  acid — in  order 
to  whip  well,  and  for  ice  cream.     Pasteurized  cream  will  not  whip 


*  See  page   321  for  management  of  separators. 


HANDLING  OF  MILK  AND  CREAM  145 

satisfactorily  unless  viscogen  is  added  to  it ;  or  a  starter,  to  develop 
slight  acidity  in  it.  The  vessel  in  which  the  whipping  is  done  should 
be  cold  and  round-bottomed ;  the  whipping  should  be  done  with 
great  speed;  and  the  whipper  should  not  be  more  than  three- fourths 
covered  with  cream.  The  cream  sold  in  this  city  (Seattle)  com- 
monly contains  from  31  to  33  per  cent,  of  fat. 

In  concluding  the  subject  of  the  production  and  handling  of 
clean  milk  and  cream,  I  wish  to  emphasize  the  fact  that  most 
farmers  can  produce  clean  milk  without  great  expense  in  ordinary 
barns  and  milk  rooms,  and  can,  by  so  doing,  make  more  money 
— even  with  the  added  expense. 

If  paper  bottles  come  into  general  use,  the  greater  part  of  all 
the  extra  trouble  and  expense  now  entailed  in  bottling  milk  at  the 
farm  will  be  abolished.  Clean  milk  may  be  shipped  in  cans,  with 
but  slight  cost  over  ordinary  milk,  and  is  just  as  satisfactory,  pro- 
viding the  cans  go  directly  to  the  consumer  and  their  contents  are 
used  wholly  by  him.  It  is  the  constant  dipping  into  cans  in  retail- 
ing small  amounts  of  milk  which  causes  the  contamination,  as  noted 
on  p.  2£. 


CHAPTER  VII 


COST   OF   PRODUCING  AND   DISTRIBUTING  CLEAN 

MILK 


A  FEW  words  first  in  regard  to  the  cost  of  production  and 
profits  on  ordinary  milk  sold  to  creameries,  for  butter  and 
other  products;  and   for  consumption  as  market  milk  in 
cities  and  towns  throughout  the  United  States. 
It  has  become  only  too  evident  to  readers  of  dairy  literature 
of  late  that  a  large  number,  perhaps  the  majority,  of  milch  cows 
in  this  country  do  not  yield  any  considerable  profit  to  their  owners. 
In  the  Cow  Census  made  by  Hoard's  Dairyman  in  Vermont 
(see  the  number  for  August  ist,  1905),  it  was  shown  that  out  of 
100  dairies,  69  did  not  pay  the  cost  of  keeping  the  cows.    The  cows 
were  natives  or  grades. 

The  estimated  cost  of  feeding  ranged  from  $33.50  to  $41.00 
per  cow,  per  year.  The  annual  profit  per  cow,  of  the  31  dairies 
which  paid  any  profit,  varied  from  43  cents  to  $22.57.  The  losses 
per  cow  annually,  in  the  dairies  which  did  not  pay,  ran  from  2 
cents  to  $21.46.  The  production  of  the  dairies  varied  from  72  to 
270  lbs.  of  butter  fat  per  cow  annually. 

Again,  in  a  report  of  the  Ohio  Cow  Census  in  Hoard's  Dairy- 
man of  April  28,  1905,  we  find  that  among  87  herds  representing 
635  cows,  with  a  yearly  average  of  3,839  lbs.  of  milk  per  cow,  the 
average  yearly  return  was  $29.93  Per  cow-  Among  this  number 
of  87  herds,  29  herds  were  kept  at  a  loss,  and  out  of  the  whole  87, 
only  26  herds  paid  a  yearly  profit  of  over  $5  per  cow  to  the  owners. 

146 


PRODUCTION  AND  DISTRIBUTION  147 

Yet  in  the  Ohio  report  we  note  one  herd  of  24  cows,  mixed 
breeds,  yielding  annually  per  cow  an  average  of  7,756  lbs.  of  milk 
and  giving  a  yearly  profit  of  $167  per  cow.  Again,  in  this  same 
report,  we  discover  another  herd  which  paid  its  owner  an  annual 
average  profit  of  10  cents  per  cow.  How  may  we  explain  such  an 
enormous  inequality  in  returns?  Let  us  compare  the  report  of  the 
two  herds : 

Herd  No.  12  Herd  No.  100 

(2  Jerseys,  3  grades)  (Mixed  Breeds) 

Cost  of  keep  per  cow  yearly $25.00  $70.00 

No.   lbs.  milk  per  cow  yearly   3,048  7>7S6 

Profit    annually    per   cow    $0.10  $167.00 

Returns  from  $1.00  invested  in  feed            $1.00  $340 

Average  price  of  milk  per  100  lbs..            $0.62  $3.05 

In  herd  No.  12,  we  find  that  the  annual  cost  of  keep  was  $25, 
and  the  yield  3,048  lbs.  of  milk,  which  brought  82  cents  per  100 
lbs.  at  the  creamery,  or  a  little  less  than  7  cents  a  gallon  the  year 
round.  A  gallon  of  milk  weighs  8.6  lbs.  Herd  No.  100  paid 
yearly  $167  per  cow,  while  the  cost  of  keep  was  $70  per  cow,  and 
the  milk  brought  a  little  over  25  cents  a  gallon,  or  over  6  cents  a 
quart  the  year  round. 

Certain  remedies  there  are  for  such  a  disparity  in  profits,  but, 
under  some  conditions,  this  disparity  can  only  be  remedied  in  part. 

In  the  cases  in  point,  the  most  essential  cause  of  the  difference 
in  profits  in  the  two  herds  is  the  difference  in  price,  which  depends 
upon  circumstances.  The  owner  of  herd  No.  100  was  near  enough 
to  the  city  of  Cleveland  to  retail  his  milk  for  over  6  cents  a  quart, 
whereas  the  product  of  herd  No.  12  was  sold  for  less  than  2  cents 
to  a  creamery. 

In  this  comparison,  there  are,  however,  other  points  to  con- 
sider: the  fact  that  the  cows  in  herd  No.  100  gave  over  twice  the 
quantity  of  milk  yielded  by  the  cows  in  herd  No.  12  is  an  important 
matter.  This  may  have  partly  depended  upon  the  care  of  the  cows 
and  feeding,  but  was  very  probably  chiefly  due  to  the  character  of 


148  CLEAN  MILK 

the  cows  themselves.  While  it  would  be  impossible  for  any  one- 
to  make  much  profit  in  milk  at  less  than  2  cents  a  quart,  yet  it  may- 
be accepted  that,  unless  a  cow  comes  up  to  a  certain  standard  in  re- 
gard to  quantity  and  quality  of  milk,  it  is  unprofitable  to  keep  her, 
and  the  sooner  that  cow  and  her  owner  are  parted  the  better.  Just 
what  that  standard  should  be  will  depend  somewhat  on  local  con- 
ditions, and  prices  of  food,  and  milk;  but,  in  a  general  way,  the 
cow  that  will  not  average  about  10  quarts  daily  during  10  months 
of  the  year  (6,000  lbs.  annually),  and  whose  milk  falls  much  be- 
low 4  per  cent,  fat,  on  the  average  (unless  the  quantity  is  very 
large),  will  not  pay  to  keep.  In  this  region,  there  are  many  herds 
of  grade  Holsteins,  containing  as  many  as  80  to  120  heads,  which 
average  16  quarts  and  over  per  cow  during  the  summer  months — 
on  pasture  alone — in  the  rich  valley  lands.  In  order  to  determine 
whether  individual  cows  are  profitable,  the  farmer  must  weigh 
the  daily  amount  and  test  the  butter  fat  of  each  cow's  (see  p.  322) 
milk  at  frequent  intervals.  Each  cow's  milk  should  be  weighed 
separately,  directly  the  cow  is  milked,  by  hanging  the  milk  pail  on 
a  balance  scale  (the  Chatillon  balance,  costing  about  $3.00  at  any 
dairy  supply  house,  is  the  best)  and  recording  the  weight  on  a 
record  sheet  which  is  gotten  up  for  this  purpose  (see  Appendix, 
p.  322.)  The  record  sheet  should  be  kept  near  the  weighing  balance 
in  a  room  devoted  to  this  purpose  in  the  barn.  To  determine  the 
percentage  of  fat  in  the  milk,  a  composite  sample — that  is,  a  sample 
of  a  mixture  of  the  same  quantity  of  night's  and  morning's  milk  of 
each  cow  for  three  days — should  be  examined  by  the  Babcock  test  at 
the  beginning  and  end  of  each  month.  The  composite  sample  is  ob- 
tained by  pouring  the  fresh  milk  from  one  pail  to  another,  and 
from  the  mixed  milk  one  should  remove  a  gill  with  a  long-handled 
dipper  at  each  milking.  The  gill  is  placed  in  a  clean  labelled  and 
covered  Mason  glass  jar,  which  is  shaken  each  time  a  new  sample 
is  added.  Fifteen  drops  of  formalin  or  half  a  powdered  B.  &  W. 
corrosive  sublimate  tablet  will  preserve  the  samples  for  days,  and'. 


PRODUCTION  AND  DISTRIBUTION  149 

two  ounces,  or  half  a  cup  of  the  composite  sample,  is  sufficient  for 
the  Babcock  test.  If  a  Babcock  tester  is  not  at  hand,  the  testing- 
may  be  clone  at  a  creamery  for  a  small  charge.  The  number  of 
pounds  of  milk  yielded  by  each  cow  monthly  should  be  multiplied 
by  the  average  per  cent,  of  fat  in  her  milk.  This  will  give  the  num- 
ber of  pounds  of  fat  in  the  cow's  milk  for  the  month,  which  should 
be  the  basis  for  comparing  her  value.  The  average  per  cent,  of  fat 
in  her  milk  for  the  month  will  be  obtained  by  adding  together  the 
results  of  the  two  fat  tests  and  dividing  the  sum  by  two.  Then  the 
general  care  and  feeding  governs  to  a  considerable  degree  the  quan- 
tity of  milk,  and  intelligent  study  of  a  good  newspaper  devoted  to 
the  dairy  industry  will  prove  of  much  value  in  this  respect.  As  we 
have  repeatedly  emphasized,  the  cleaner  the  milk  the  better  it  is  for 
any  purpose,  and  the  farmer  who  devotes  himself  to  producing  a 
clean  milk  should  receive  a  larger  price  for  it.  Of  course,  local 
conditions  will  largely  determine  the  advisability  of  investing  extra 
money  and  time  in  the  food,  care  and  cost  of  cows,  but  very 
rarely  will  it  pay  to  keep  cows  which  do  not  pay  for  their  keep.  It 
may  be  necessary  to  keep  cows  for  their  manure,  but  this  is  usually 
considered  as  merely  offsetting  the  cost  of  their  care,  and  so  the 
cost  of  keeping  cows  is  commonly  figured  in  estimating  the  cost 
of  their  food.  The  yearly  cost  of  feeding  a  cow  varies  from  $17 
to  $90,  averaging  perhaps  throughout  the  United  States  about 
$35.  At  the  experiment  stations,  with  the  best  selected  stock  and 
breeds  and  the  most  expert  care,  the  cost  of  producing  1  quart  of 
milk  varies  from  0.7  to  2.9  cents,  according  to  breed  and  individual 
characteristics  of  cows.  When  a  farmer  receives  on  the  average 
2  cents  or  less  per  quart  for  milk,  there  can  be  little  profit  to  him. 
Yet  two  cents  was  about  the  price  paid  for  years  to  farmers  who 
have  shipped  ordinary  market  milk  to  New  York  City 

It  has  been  stated  by  many  authorities  that  ■  one-third  of  the 
cows  in  this  country  is  kept  at  a  loss;  that  one-third  just  about 
pays  for  its  keep,  and  that  one-third  pays  a  profit  to  their  owners. 


i5o  CLEAN  MILK 

The  most  striking  fact  which  impresses  one  in  this  whole  matter 
of  profit  in  milk  production  is  the  folly  of  keeping  poor  cows.  A 
poor  cow  makes  a  poor  owner. 

The  production  and  transportation  of  clean  milk  is  attended 
with  much  greater  expense  than  that  of  ordinary  or  "  market  "' 
milk. 

The  following  figures,  showing  the  cost  of  milk  production 
and  distribution,  must,  of  course,  be  considered  only  approximate. 
Local  conditions  alter  circumstances  tremendously.  Thus  in  this 
region  (Seattle,  Wash.),  the  climate  is  so  mild  that  ice  has  to  be 
used  on  the  milk  during  transportation  on  the  railroad  and  delivery 
in  the  city  wagon  the  year  round.  Then  again,  the  city  is  very 
hilly  and  the  streets,  many  of  them,  very  bad,  and  the  milk  route 
is  not  concentrated  in  a  thickly  settled  district. 

We  may  place  the  average  cost  of  the  production  throughout 
the  country  of  ordinary  market  milk  at  2  to  2^  cents  per  quart  as 
the  result  of  the  figures  obtained  from  the  experiment  stations  in 
the  past.  Owing  to  the  exceptional  high  cost  of  cow  feed  and 
labor  in  recent  years,  Dr.  E.  B.  Voorhees,  of  the  N.  J.  Exper.  Sta., 
has  lately  (1907)  computed  that  it  costs  the  farmer  from  4.7  to 
6.55  cents  per  quart  to  raise  milk.  The  range  in  the  price  of  the 
cost  quoted  depends  upon  the  cost  of  the  investment  and  labor, 
the  cleanliness  of  the  milk  produced,  and  also  whether  the  farmer 
charges  more  than  the  cost  of  ordinary  farm  labor  for  his  time. 
Perhaps  the  average  figure  hitherto  paid  the  farmer  for  ordinary 
market  milk  hereabouts  is  3^3  cents  a  quart.  This  does  not  differ 
materially  from  the  price  paid  in  many  parts  of  the  country.  At 
present  (Feb.,  1908)  the  farmer  is  receiving  about  \Y^  cents  net 
for  ordinary  market-milk  in  this  locality  (Seattle,  Wash.)  which 
retails  at  10  cents  a  quart  for  bottled  milk. 

The  cost  of  producing  clean  milk  in  this  region,  over  and' 
above  that  of  ordinary  milk,  may  be  set  down  at  2  cents  a  quart. 
This  includes  the  extra  care  necessitated  in  the  barn  and  dairy,. 


PRODUCTION  AND  DISTRIBUTION  151 

the  fuel  for  running  the  boiler,  the  ice,  etc.  In  the  milk  room, 
there  is  the  washing  and  sterilizing  of  all  the  bottles  and  apparatus, 
and  the  bottling  of  milk  and  packing  of  the  bottles  in  boxes  with 
ice.  The  farmer  must  make  a  considerable  outlay  for  the  parapher- 
nalia in  his  milk  room,  but  the  bottles,  in  this  vicinity,  are  sup- 
plied by  the  distributors  in  the  city. 

The  minimum  price  paid  to  the  producer  is  about  6  cents  a 
quart — the  bottles,  cases  and  freight  being  paid  by  the  distributor. 
The  highest  price  paid  in  any  part  of  the  country  to  the  pro- 
ducer for  bottled,  certified  milk  delivered  at  the  local  R.  R.  station 
is  at  present  10  cents. 

The  cost  of  transporting  milk  by  rail  in  bottles  to  the  city, 
some  30  miles,  is  1  cent  a  quart  in  this  region,  and  it  costs  about 
the  same  in  other  cities.  This  figure  includes  the  cost  of  carriage 
for  the  galvanized  iron  box,  holding  one  dozen  bottles  and  ice, 
the  whole  weighing  68  lbs.,  and  also  the  return  of  empty  bottles  and 
cases  to  the  farm. 

The  cost  of  distributing  clean  milk  is  much  greater  than  ord- 
inary milk,  when  ice  is  used,  owing  to  the  weight  of  the  ice  and 
cases  holding  the  bottles  and  the  fact  that  customers  of  high  priced 
milk  are  apt  to  be  scattered  about.  The  cost  of  distribution  of 
bottled  milk  has  been  set  down  at  two  cents  a  quart,  but  three  cents 
a  quart  would  be  nearer  the  mark  in  this  vicinity  for  milk  sold 
on  ice  the  year  round.  The  farmer  should  then  receive  at  least 
seven  cents  a  quart  net  for  bottled  certified  milk  as  the  minimum 
figure,  according  to  my  experience  in  this  region,  or  about  double 
what  he  has  received  for  ordinary  market  milk.  This  is  a  uniform 
price  for  the  year  around.  For  the  ordinary  milk  he  has  hitherto 
received  from  nine  cents  to  sixteen  cents  per  gallon,  at  different 
seasons,  and  it  has  retailed  at  about  seven  cents  a  quart  (bottled). 
The  distributor  of  milk,  if  he  pays  the  farmer  seven  cents 
per  quart  for  bottled  certified  milk  on  ice  and  one  cent  per  quart 
•freight,  should  get  twelve  cents  as  a  minimum  price  per  quart  to 


1 52  CLEAN  MILK 

make  any  profit.  This  figure  is  a  low  estimate  when  various  un- 
avoidable losses  are  taken  into  account,  as  repairs  and  deterioration 
of  milk  boxes,  harness,  sickness  and  death  of  horses,  loss  of  ac- 
counts, bottles,  etc.  I  believe  that  seven  to  eight  cents  a  quart  for 
bottled  milk,  for  the  farmer,  and  twelve  to  fifteen  cents  a  quart  for 
the  distributor  of  clean  milk  in  the  city,  is  a  safe  estimate  as  a  basis 
on  which  a  profitable  business  for  both  may  be  done.*  The  price 
of  certified  milk  is  on  the  average  sold  retail  for  5  cents  more  a 
quart  than  ordinary  market  milk,  the  price  of  market  milk  vary- 
ing with  the  locality.  It  is  impossible  to  keep  up  the  standard 
of  clean  milk  unless  a  reasonable  profit  is  being  made  at  both 
ends  of  the  business. 

When  milk  is  bottled  and  retailed  in  the  city  the  cost  is  about 
as  follows : 

Freight   and   cartage    iy2  cents. 

Bottling  and  icing iy2    cents. 

Wagon    delivery    I       cent. 

Office  expenses  per  quart  %    cent. 

Total  cost   of  handling    4%  cts  per  qt. 

If  milk  is  delivered  by  wagon  directly  from  farm  to  consumer, 
the  freight,  cartage,  and  office  expenses  are  cut  out  and  labor  is  often 
cheaper  in  country  towns,  so  that  the  cost  of  handling  and  delivering 
milk  direct  from  the  farm  to  the  consumer  would  be  from  2  to  3 
cents  a  quart. 

Every  step  by  which  the  milk  is  improved  costs  money  in  labor 
or  material,  and  it  has  been  my  experience  that  it  is  useless  to  ex- 


*  In  Hoard's  Dairyman  of  a  recent  date  the  proportionate  receipts  from 
quart  of  milk  retailing  for  8  cents  in  New  York  City,  are  given  as  follows: 

Cents 

Producer  receives 2.75 

Railroad  for  transporting,  receives   0.5 

Dealers  handling,  bottling  and  distributing  the  same,  receive    4.75 

8.00 


PRODUCTION  AND  DISTRIBUTION  153 

pect  the  farmer  to  carry  out  all  the  necessary  details  of  cleanliness 
unless  he  can  really  afford  to  do  so.  The  actual  price  at  which 
certified  milk  retails  varies  in  various  cities  from  eight  to  thirty 
cents  per  quart.  Rich  milk,  as  milk  containing  five  per  cent,  fat, 
should  bring  a  higher  price,  though  it  is  not  preferable  for  infant 
food — rather  the  reverse,  as  we  have  noted. 

In  this  vicinity  there  has  been  an  attempt  to  employ  one  farm 
as  a  bottling  station  in  which  the  utensils  of  all  the  farms  are 
washed  and  sterilized  and  to  which  milk,  which  has  been  milked 
and  cooled  at  neighboring  farms,  is  brought.  When  the  milk  was 
supplied  by  the  farm  doing  the  bottling,  and  one  other  about  a 
mile  away,  the  result  was  very  good.  The  highest  number  of 
bacteria  in  the  milk  bottled  from  these  two  farms  was  17,000  per 
cubic  centimeter  during  six  months.  Pressure  being  brought  to 
bear  to  increase  the  milk  supply,  several  more  farms  were  taken 
into  the  combination  with  disastrous  results.  This  unfortunate 
outcome  was  largely  due  to  the  fact  that  the  owners  of  the  farms 
which  were  taken  into  the  combination  last  had  not  time  given 
them  to  arrange  their  barns  and  milk-rooms  properly,  and  had 
not  got  into  the  routine  necessary  to  produce  clean  milk.  Whether 
an  arrangement  of  this  kind  for  producing  certified  milk  is  wholly 
practicable  is  somewhat  doubtful.  There  are  so  many  more  op- 
portunities for  contamination  of  the  milk  with  dirt  and  germs.  If 
a  like  attempt  is  elsewhere  undertaken,  the  milk  from  each  farm 
should  be  examined  once  a  week  before  bottling  it  and  mixing1 
it  with  milk  from  the  other  farms,  to  ascertain  the  number  of 
bacteria  and  the  amount  of  fat  in  the  milk.  The  plan  has  the 
advantage  of  bringing  several  farmers  to  a  higher  standard  than 
would  otherwise  be  possible,  and  enables  the  farmer  who  supplies 
all  the  dairy  apparatus  to  make  a  more  economical  use  of  his  plant. 

The  central  plant,  at  which  all  milk  pails,  strainers,  cans  and 
other  milk  utensils  are  washed  and  sterilized  before  each  milking, 
may  be  a  creamery.     Farmers  should  deliver  milk  within  an  hour 


i54  CLEAN  MILK 

after  milking.  In  the  instance  just  cited  the  farmers  receive  4^4 
to  5  cents  for  milk  in  cans,  and  the  central  plant  7  cents  a  quart 
for  milk  in  bottles  delivered  at  the  nearest  R.  R.  station.  Such 
milk,  if  not  up  to  certified  standard,  should  be  much  superior  to 
ordinary  market  milk — especially  if  obtained  from  tuberculin  tested 
cows. 

When  an  individual  wishes  to  begin  to  sell  clean  milk  in  a 
neighborhood  in  which  certified  milk  is  unknown,  it  is  well  for  him 
first  to  interest  the  local  medical  profession  in  the  project.  The 
local  medical  society,  or  individual  physicians,  should  form  a  com- 
mittee with  laboratory  facilities.  The  work  can  be  done  under  the 
committee's  direction  by  an  intelligent  druggist.  Any  dairy,  sup- 
plying clean  milk,  may  receive  a  certificate  from  the  medical  com- 
mission, if  the  milk  fulfils  the  required  standard,  as  the  result  of 
weekly  laboratory  examinations  and  inspections  by  a  veterinarian 
at  intervals  of  two  weeks.  Providing,  however,  that  the  milk  has 
fulfilled  all  the  requirements  of  the  milk  commission  for  a  proba- 
tionary period  of  at  least  two  months  prior  to  the  granting  of  a 
certificate. 

Estimation  of  the  Value   of  Milk  and  Cream  for  Ordinary 
Purposes 

The  value  of  milk  and  cream  throughout  the  country  is  gen- 
erally determined  by  the  price  of  butter.  And  the  butter  maker 
pays  for  milk  or  cream  according  to  the  pounds  of  butter  fat  each 
contains.  Clean  milk  or  cream  of  the  purity  of  the  certified  milk 
or  cream,  however,  bring  a  price  greatly  above  that  fixed  by  a 
butter-fat  valuation. 

In  churning  a  pound  of  butter  fat  (in  milk  or  cream)  into 
"butter  there  is  a  gain ;  that  is,  a  pound  of  butter  fat  will  produce 
more  than  a  pound  of  butter.  The  weight  of  the  butter  fat  sub- 
tracted from  the  weight  of  the  butter  (made  from  it)  is  the  over- 


PRODUCTION  AND  DISTRIBUTION  155 

run.*  The  reason  for  this  gain  in  churning  butter  fat  into  butter 
is  that  there  are  ingredients  in  the  milk  or  cream,  and  also  the  salt 
contributed  by  the  butter  maker,  which  add  to  the  fat  in  the 
butter.  Thus  butter  contains  on  the  average  about  84  per  cent, 
of  fat,  and  the  remaining  16  per  cent,  consists  of  water  (12  per 
cent.),  and  curd  (1  per  cent.),  salts  (2.5  per  cent.),  and  milk  sugar 
(0.5  per  cent.).  This  is  the  average  composition  of  butter, f  but 
the  water  may  vary  in  amount  from  8  to  16  per  cent,  and  the  fat 
proportionately.  The  overrun,  then,  does  not  depend  upon  nor 
refer  to  the  percentage  of  fat  in  butter..  It  is  always  estimated  by 
determining  the  fat  in  the  milk  or  cream  by  the  Babcock  test,  and 
then  subtracting  the  weight  of  the  fat  from  the  weight  of  the  re- 
sulting butter. 

The  amount  of  butter  which  can  be  made  from  a  given  weight 
of  cream  depends  upon  the  amount  of  fat  it  contains.  The  richer 
in  fat  it  is,  the  less  the  loss  of  fat  in  the  buttermilk  in  churning. 
Thus  buttermilk  contains  about  0.3  per  cent,  of  fat,  and  cream  con- 
taining 15  per  cent,  of  fat  would  yield  almost  four  times  as  much 
buttermilk  as  cream  containing  40  per  cent.  fat.  Moreover,  the 
buttermilk  from  rich  cream  contains  absolutely  less  fat  (less  than 
0.3  per  cent,  fat)  than  that  derived  from  churning  thin  cream. 
Then  there  are  mechanical  losses  of  fat  from  cream  and  butter 
sticking  to  various  utensils  used  in  the  course  of  making  and  hand- 
ling butter.  This  naturally  influences  the  amount  of  butter  which 
can  be  made  from  a  given  quantity  of  fat  in  milk  or  cream.  Two 
to  five  pounds  of  butter-fat  may  thus  be  wasted  for  every  hundred 
pounds  handled. 


*  For  detailed  information  concerning  overrun,  see  Bull.  129,  Some 
Creamery  Problems,  E.  H.  Farrington,  Univ.  Wis.  Agric.  Exper.  Sta.,  to 
which  the  author  is  greatly  indebted. 

t  Since  the  U.  S.  Pure  Food  Act  of  1906  requires  that  butter  shall  contain 
82.5  per  cent,  of  butter  fat  as  a  minimum,  it  follows  that  creamery  butter  will 
not  in  future  exceed  this  requirement.  This,  therefore,  may  be  regarded  as 
the  present  average  content  of  fat  in  butter. 


156  CLE  AX  MILK 

The  Overrun. — As  an  example  we  will  estimate  the  overrun 
in  making  116  pounds  of  butter  from  2,500  pounds  of  4  per  cent. 
milk.  We  first  determine  the  weight  of  fat  in  the  milk :  2,500 
pounds  multiplied  by  .04  equals  100  pounds  of  fat.  Subtracting 
this  from  116  pounds  of  butter  made  from  it  gives  us  the  overrun 
as  16  pounds,  or  16  per  cent.,  because  it  is  16  per  cent,  of  the  100 
pounds  of  fat  in  the  milk. 

The  overrun  is  usually  less  on  account  of  various  losses.  Thus 
in  skimming  the  milk  in  the  separator  there  is  a  loss  of  about  0.1 
per  cent,  of  fat  contained  in  the  skim  milk;  after  churning  there 
is  the  loss  in  the  buttermilk  we  have  noted  equal  to  0.3  per  cent. 
fat  in  the  buttermilk;  and  there  are  the  mechanical  losses  we  have 
referred  to,  equivalent  to  about  2  to  5  per  cent,  of  the  total  fat  in  the 
milk.  So  of  the  100  pounds  of  fat  in  the  2.500  pounds  of  4  per 
cent,  milk  there  may  be  only  93.13  pounds  of  fat  available,  which 
would  make  110.86  pounds  of  butter  containing  84  per  cent,  of  fat. 
Subtracting  from  this  110.86  pounds  of  butter  the  100  pounds  of 
fat  contained  in  the  2,500  pounds  of  milk  gives  10.86  pounds,  or 
10.86  per  cent.,  as  the  amount  of  the  overrun.  The  overrun  varies, 
not  only  owing  to  the  conditions  noted,  but  also  as  the  churning 
leaves  more  or  less  water  in  the  butter,  and  according  to  the  accu- 
racy of  testing  the  milk  or  cream  for  fat,  and  in  weighing  the  same. 
The  normal  range  in  overrun  for  milk  varies  from  10  to  15  per 
cent.  An  overrun  above  or  below  these  figures  demands  an  in- 
vestigation. The  overrun  from  cream  is  somewhat  higher  than 
these  figures,  since  there  is  no  loss  from  skimming,  as  from  milk. 
The  cream  overrun  varies  from  16  to  20  per  cent. 

Estimation  of  the  overrun  is  not  in  any  way  essential  in  cal- 
culating the  money  due  patrons  of  a  creamery  for  milk  or  cream. 
The  simplest,  fairest,  and  generally  most  satisfactory  way  is  to 
weigh  and  test  each  sample  of  milk  or  cream  of  the  patron's  for 
butter-fat  and  subtracting  the  cost  of  making  the  butter  from  its 
selling  price,  to  give  the  balance  of  the  returns  to  the  patrons  in 


PRODUCTION  AND  DISTRIBUTION  157- 

proportion  to  the  butterfat  they  supplied.  Thus,  if  232  pounds  of 
butter  were  made  during  a  given  time  from  200  pounds  of  butter- 
fat,  and  the  butter  sold  at  25  cents  a  pound,  the  butter  fetched 
$58.00.  Subtracting  from  this  4  cents  a  pound  for  making  gives 
$48.72  to  be  divided  among  the  patrons  according  to  the  amount 
of  butter-fat  each  supplied.  48.72  divided  by  200  gives  us  24.35 
cents  as  the  price  to  be  paid  each  patron  for  each  pound  of  fat  sup- 
plied in  his  milk  or  cream.  The  following  correction  should,  how- 
ever, be  made: 

The  milk  patron  is  paid  for  all  the  butterfat  in  his  milk  brought 
to  the  creamery  while  the  cream  patron  is  not,  as  part  of  the  butter- 
fat in  his  milk  remains  at  the  farm  in  the  skim  milk.  Besides,  he 
saves  the  creamery  the  expense  of  skimming  the  milk.  Therefore, 
in  calculating  the  amount  of  fat  supplied  the  creamery  by  its  patrons 
the  cream  patron  should  be  credited  not  only  with  the  fat  actually 
present  in  his  cream,  but  to  it  is  added  3  per  cent,  of  its  total  to 
put  him  on  the  same  basis  as  the  milk  patron.  (The  0.12  fat  lost 
in  the  skim  milk  from  hand  separators  equals  about  3  per  cent,  of 
total  fat  in  the  whole  milk.) 

Thus,  supposing  four  patrons  supplied  the  200  pounds  of  fat, 
as  follows: 

Corrected  Weight 
Fat.  of  Fat. 

Milk    patron     32.5  lbs.  32.5  lbs. 

45-5  lbs.  45-5  lbs. 

Cream     «*  62  X  .03=63.8  63.8 

"  60  X  .03=61.8  6i-8 


200  lbs.  208.6  lbs. 

We  correct  the  weight  of  fat  supplied  by  the  cream  patrons, 
as  above,  and  divide  the  price  the  butterfat  brought  ($48.70)  by 
the  corrected  weight  of  the  fat  (203.6  lbs.),  which  gives  23.92 
cents.  This  is  the  price  per  pound  of  butterfat  to  pay  the  patron  of 
the  creamery  according  to  the  corrected  weights  of  fat  in  the  last, 
column  above. 


158  CLEAN  MILK 

To  consider  this  matter  more  in  detail,  especially  in  regard  to 
the  price  a  given  quantity  of  milk  will  bring  if  sold  in  different 
forms,  suppose  we  take,  for  example,  290  gallons  of  milk.  A  gallon 
of  milk  weighs  8.66  pounds,  290  gallons  of  milk  will  then  weigh 
approximately  2,500  pounds,  and,  containing  4  per  cent,  of  fat,  will 
give  us  100  pounds  of  fat.  In  converting  this  into  butter  the  first 
process  will  be  to  skim  the  milk  in  a  separator,  which  will  give  us  a 
loss  at  the  creamery  of  0.1  per  cent,  fat  in  the  skim  milk.  The  skim 
milk  may  be  assumed  to  be  85  per  cent,  of  the  whole  milk ;  85  per 
cent,  of  2,500  pounds  equals  2,125  pounds  skim  milk;  2,125  mul- 
tiplied by  0.001  equals  2.12  pounds  of  fat  in  the  skim  milk.  Sub- 
tracting this  from  the  100  pounds  of  fat  in  the  290  gallons  of  milk 
gives  us  97.88  pounds  of  fat  in  the  cream  arising  from  this  amount 
of  milk;  326  pounds  of  30  per  cent,  cream  will  contain  just  about 
this  amount  of  fat,  that  is,  97.8  pounds.  In  churning  this  into 
butter  there  will  be  a  loss  of  0.3  per  cent,  of  the  total  fat  in  the 
buttermilk.  The  amount  of  buttermilk  is  the  difference  between 
the  weight  of  the  cream  and  the  fat  in  the  cream,  or,  roughly,  10 
per  cent,  of  the  whole  milk.  In  326  pounds  of  30  per  cent,  cream 
there  are  97.8  pounds  of  fat;  subtracting  this  from  the  weight 
of  the  cream  gives  us  the  weight  of  the  buttermilk,  228  pounds; 
multiplying  this  by  0.003  equals  .684  pounds,  or  the  loss  of  fat 
in  buttermilk;  subtracting  this  loss  of  fat  in  buttermilk  from  the 
fat  in  the  30  per  cent,  cream  gives  us  97.12  pounds  of  fat  for 
butter.  This  would  make  117  pounds  of  butter  containing  83  per 
cent,  of  fat.  (To  arrive  at  this  result  we  divide  97.12  by  0.83, 
equals  117.)  Then,  to  get  the  (theoretical)  overrun,  we  subtract 
the  100  pounds  of  fat  in  the  original  milk  from  the  100  pounds  of 
butter  made  from  it  (117),  which  gives  us  17  as  the  percentage 
of  overrun.  We  will,  however,  have  mechanical  losses  equal  to 
2  or  3  pounds,  so  we  will  consider  that  we  shall  actually  get  114 
pounds  of  butter  from  290  gallons  of  4  per  cent.  milk.  The  cost 
of  making  a  pound  of  butter  varies  from  four  cents  to  a  fraction 


PRODUCTION  AND  DISTRIBUTION  159 

Jess  than  two  cents  in  large  and  well  conducted  creameries.  In 
calculating  the  amount  of  butter  which  can  be  made  from  a  given 
amount  of  butterfat  we  add  one-seventh  to  butterfat  in  milk  and 
one-sixth  to  butterfat  in  cream.  The  butterfat  in  cream  makes  a 
larger  amount  of  butter,  because  there  is  not  the  loss  of  fat  in 
skim  milk.  With  butter  wholesale  at  22  to  40  cents  a  pound,  and 
subtracting  4  cents  for  making,  the  butter  would  net  the  farmer 
$20.52  to  $45.60  for  his  290  gallons  of  milk. 

Cream  is  often  bought  in  cities  by  ice  cream  and  cream  dealers 
at  a  rate  of  2  cents  (more  or  less)  above  the  value  of  the  cream 
for  butter;  that  is,  if  butter  was  22  cents  the  cream  would  be  bought 
at  a  valuation  of  butter  at  24  cents;  326  pounds  of  30  per  cent, 
cream  equals  about  40  gallons  (a  gallon  of  30  per  cent,  cream 
weighs  nearly  8  pounds  actually;  if  free  from  much  air  or  gas, 
8.3  pounds)  this,  making  114  pounds  of  butter  valued  at  24  cents 
to  42,  2  cents  above  current  butter  price,  would  give  $27.36  to 
$47.88  as  the  price  for  290  gallons  of  milk  in  form  of  cream.  In 
either  case  the  farmer  has  the  skim  milk  to  feed,  which  may  be 
roughly  valued  at  35  cents  per  100  pounds  for  feeding,  and  11 
cents  additional  (in  passing  through  the  calves)  for  fertilizer; 
2,125  pounds  of  skim  milk  at  46  cents  per  100  pounds  equals 
$9.77;  290  gallons  of  ordinary  market  milk  may  bring  the  farmer 
12  to  19  cents  a  gallon  net  if  sold  for  city  consumption,  equals 
$34.80  to  $55.10. 

For  clean,  pure  30  per  cent,  cream,  bottled  at  the  farm,  as 
much  as  $1.20  to  $1.40  per  gallon  should  be  gotten.  If  the 
cream  is  shipped  in  cans  on  ice  or  in  special  ice-containing  cans 
(see  p.  123),  it  should  bring  $1.00  to  $1.20  per  gallon  for  a  clean 
article.  If  the  milk  were  sold  in  bottles  from  the  farm  as  certified 
milk  it  should  bring  the  farmer  7  cents  a  quart,  delivered  on  ice 
at  the  nearest  railroad  station,  at  least,  which  amounts  to  $81.20 
for  the  290  gallons. 


160  CLEAN  MILK 

The  returns  from  290  gallons  of  4  per  cent,  milk,  sold  as: 
follows,  are: 

As  114  pounds  of  butter,  at  22  to  40  cents  per  lb.  with 

value  added  of  skim  milk  to  farmer  $30.29  to     $55.30 

As  ordinary  milk  in  cans  at  12  to  19  cents  per  gallon..  34.80  "         55-IO 

As  cream,  with  value  of  skim  milk  added    37.13  "        47.88 

Clean,  cooled  cream  shipped  on  ice  in  cans,  with  value  of 

skim    milk    added 49-77  "         57-77 

Clean,  cooled  bottled  cream,  with  value   of  skim   milk 

added    57-77"        65.77 

Certified    bottled    milk    81.20 

These  figures,  of  course,  cannot  be  taken  as  applying  pre- 
cisely to  conditions  in  any  given  locality,  or  to  any  one  time.  A 
considerable  range  in  the  prices  of  butter,  cream  and  milk  will 
be  observed  in  the  foregoing  table.  As  great  fluctuations  occur,, 
however,  owing  to  the  season  or  locality,  the  higher  prices  rep- 
resent those  prevalent  hereabouts  at  present  (Seattle,  Feb.  1908). 
Certified  milk  is  sold  at  the  same  uniform  price  the  year  round, 
as  it  is  not  affected  directly  by  the  laws  of  supply  and  demand  at 
the  present  time.  The  figures  are  only  given  to  show  how  to 
calculate  approximately  relative  returns  from  milk  products,  and 
it  will  be  found  that  the  returns  for  ordinary  market  milk  are  about 
the  same  as  can  be  gotten  from  a  creamery  for  butter.  Moreover, 
the  higher  returns  received  from  the  sale  of  bottled  certified  milk 
must  not  be  taken  as  necessarily  indicating  that  the  maximum  profit 
accrues  from  selling  milk  in  this  form.  It  may  well  be  that  the 
extra  cost  of  labor,  fuel,  ice  and  plant,  required  for  its  production, 
will  amount  to  2  or  3  cents  a  quart. 

It  is  impossible  to  fix  the  value  of  skim  milk  for  feeding  and 
fertilizer,  as  it  depends  upon  such  variable  factors  as  the  value 
of  veal  and  pork,  the  price  of  other  food  stuffs,  the  value  of 
milk  in  the  locality  and  the  knowledge  of  the  person  using  it  as  to 
the  best  way  to  feed  it.  Skim  milk  is  said  to  be  worth  $1.00  a 
hundredweight  in  midwinter  to  feed  to  hens  with  corn  meal,  while- 


PRODUCTION  AND  DISTRIBUTION  161 

for  feeding  calves  it  is  valued  from  20  to  40  cents  a  hundred- 
weight, according  as  the  price  of  veal  varies  from  $3  to  $5  per 
100  pounds.  To  be  fed  with  most  economy  to  calves  it  should 
be  given  in  proportion  of  two  to  three  pounds  of  skim  milk  to 
every  pound  of  meal.  I  have  known  skim  milk  to  be  used  with 
excellent  result  when  poured  on  the  soil  as  a  fertilizer  in  the  culti- 
vation of  cauliflowers.  H.  B.  Gurler  claims  that  for  feeding  pigs 
skim  milk  is  worth  one-half  as  much  per  100  pounds  as  corn  is 
worth  per  bushel. 


CHAPTER  VIII 


SOME  HINTS  CONCERNING  MILK  DISTRIBUTION 


ONE  of  the  chief  difficulties  to  contend  with  in  retailing  milk 
is  the  almost  instinctive  desire  of  the  public  to  get  their 
milk  in  the  early  morning  hours.  Customers  apparently 
labor  under  the  false  impression  that  milk  left  in  the  early 
morning  hours  is  a  product  of  the  night,  like  the  dew,  or  early 
morning  paper  on  the  doorstep.  As  a  matter  of  fact,  milk  which 
is  delivered  before  8  a.  m.  at  the  customer's  door  is  usually  twenty- 
four  to  thirty-six  hours  old.  This  happens  because  milk  trains 
<lo  not  often  arrive  before  8  A.  m.,  and  the  milk  on  these  trains 
represents  that  milked  the  night  before  and  in  the  early  morning 
of  the  day  of  arrival  in  the  city.  This  milk  is  often  delivered  in 
the  early  morning  of  the  day  following  that  of  its  arrival  in  the  city. 
Although  we  have  seen  that  clean  milk  may  be  kept  sweet  on 
ice  for  several  weeks  (see  p.  22),  yet  we  have  also  learned  that 
germs  will  develop  in  milk  at  a  temperature  of  40  degrees  Fahren- 
heit, or  lower,  and  that  they  may  increase  tremendously  at  low 
temperatures  in  time  (see  pp.4,  38).  It  is  safer,  therefore,  that 
clean  milk  be  not  sold  when  it  is  twenty- four  hours  old ;  and  the 
requirements  of  some  medical  societies  certifying  milk  forbids  its 
sale  after  it  is  twenty-four  hours  old. 

The  milk  arriving  in  the  city  on  any  morning  will  represent 
the  night's  milk  of  the  previous  day  and  the  milk  which  has  been 

milked  very  early  on  the  morning  of  its  arrival.     Or,  as  in  the 

162 


HINTS  CONCERNING  DISTRIBUTION  163 

-writer's  experience,  the  milk  arrives  in  the  morning,  before  7  a.  m., 
representing  the  milk  of  the  previous  night,  while  the  morning's 
milk  arrives  at  noon  and  the  delivery  of  the  milk  is  continued  from 
7  a.  m.  to  6  P.  M. 

In  some  localities — where  night's  milk  cannot  be  kept  cool 
— only  the  morning's  milk  is  sent  to  the  city,  the  night's  milk  going 
to  the  creamery. 

We  have  found  it  possible  by  instructing  the  customers  con- 
cerning the  folly  of  demanding  delivery  of  milk  to  their  doors  in 
the  early  morning  hours  to,  in  a  measure,  ignore  this  desire,  and 
so  distribute  milk  during  the  whole  of  the  day,  with  an  interrhis- 
sion  of  an  hour  for  the  men  and  horses  at  noon. 

Milk  consumers  should  be  instructed  as  to  the  care  of  milk 
at  home.  That  the  essentials  consist  in  keeping  the  milk  cold  in  a 
covered  and  absolutely  clean  utensil. 

Thus  the  milk  bottle  itself  is  the  best  utensil  in  which  to  keep 
the  milk.  The  top  and  outside  of  milk  bottles  should  be  rinsed  with 
clean  water  before  opening  them — unless  the  inner  cardboard  cap  is 
covered  with  an  outer  paper  cap,  as  certified  milk  is  commonly 
treated. 

The  bottle  should  be  kept  capped  and  on  ice,  unless  in  a  very; 
cold  room  or  in  cold  water. 

Milk  should  be  kept  then  usually  in  a  refrigerator  and  away 
from  other  foods  which  easily  impart  their  odor  to  milk.  Cover- 
ing milk  prevents  dust  and  germs  and  odors  from  contaminating 
it. 

If  milk  is  received  from  a  can  it  is  well  to  collect  it  in  a  clean, 
covered,  glass  preserving  jar.  Milk  should  never  be  left  on  the 
doorstep  to  become  warmed  by  the  sun  or  frozen,  as  the  case  may 
be.  Fresh  milk  must  never  be  mixed  with  old  milk  since  the  latter 
acts  as  a  starter  by  adding  germs  to  the  fresh  supply.  Customers 
should  be  instructed  to  rinse  milk  bottles,  as  soon  as  empty,  in  luke- 
warm water  and  not  to  use  them  for  any  other  purpose.     If  scarlet 


164  CLEAN  MILK 

fever,  diphtheria  or  typhoid  fever  exist  on  the  premises  the  milk 
dealer  should  refuse  to  leave  bottles  or  take  back  any  empty  bottles. 

In  such  a  case  milk  may  be  poured  from  the  bottle  into  a  utensil 
furnished  by  the  customer  and  left  outside  the  premises  for  that 
purpose.  The  utensil  belonging  to  the  customer  should  not  be 
touched  by  the  milkman. 

Customers  should  be  told  that  all  utensils  in  which  milk  is 
kept  should  only  be  cleaned  by  rinsing  in  lukewarm  water,  by 
washing  in  soap  and  water,  by  rinsing  in  clean  water,  and  finally 
by  scalding  in  boiling  water.  The  utensil  should  then  be  left  to 
drain  and  dry  without  touching  a  towel  to  it. 

It  is  well  for  milk  producers  to  supply  their  customers  with 
instructions  to  the  above  effect. 

The  nature  of  local  conditions  will  determine  to  a  considerable 
extent  the  cost  of  delivery  and  also  many  of  the  practical  details 
as  to  the  kind  of  wagon,  bottle  boxes,  use  of  ice  in  wagons,  etc. 
To  obviate  overhauling  of  the  boxes  in  the  wagons  they  should  not 
be  piled  in  layers  one  over  the  other.  This  may  be  accomplished 
by  means  of  a  special  arrangement  in  the  wagon  shown  in  Fig.  48.. 
I  have  personally  had  no  experience  with  this  wagon,  but  have 
considered  that  simplicity  is  one  of  the  chief  aims  in  any  scheme, 
and  by  making  the  wagon  wide  and  long  enough  one  can  carry 
about  all  the  boxes  of  bottles  proper  on  the  floor.  Thus  the  wagon 
body  may  hold  fifteen  boxes  on  the  floor  and  five  or  more  placed 
directly  on  top  of  the  first  tier  without  any  inconvenience  in  hand- 
ling them.  These  twenty  boxes  weigh,  when  filled  with  milk, 
bottles,  and  ice,  about  1,400  pounds  and  constitute  a  load  in  a  hilly 
city  for  two  horses.  In  the  wagons  built  under  our  direction  there 
is  a  round  hole  cut  in  each  side  of  the  top,  a  few  inches  above 
the  floor,  about  fourteen  inches  in  diameter  and  just  back  of  the 
driver's  seat.  This  permits  of  bottles  being  taken  out  of  the  boxes 
in  the  wagon  without  requiring  the  driver  to  mount  the  front  of 


HINTS  CONCERNING  DISTRIBUTION 


165 


the  wagon.  A  wide  step  is  affixed  to  the  wagon  behind  on  which 
the  driver  stands  when  getting  bottles  at  the  rear  of  the  wagon. 
The  floor  is  of  sheet  iron  with  an  open  slit  at  either  side  running- 
the  whole  length  to  permit  water  draining  through  the  bottom 
of  the  wagon.  There  is  a  high  tail-board,  and  the  upper  part  of  the 
top  of  the  wagon  at  the  back  is  closed  in  for  perhaps  two  feet  from 
the  top  to  keep  out  the  sun.     Each  of  the  boxes  contains  twelve. 


■quart  milk  bottles  and  the  load  consists  of  240  quarts.  The  capac- 
ity of  the  wagon  arranged  for  sliding  bottle-cases  is  a  maximum  of 
204  quarts,  but  special  arrangements  might  allow  of  greater  capac- 
ity. A  wagon  similar  to  that  seen  in  Fig.  49  may  be  used  for 
bottles  alone  and  will  have  a  capacity  of  256  quarts.  The  wooden 
cases  slide  and  may  be  easily  reached  from  the  seat  as  well  as 
rear.  Ice  cannot,  however,  be  used  on  the  bottles  in  this  wagon. 
Such  wagons  have  been  used  with  an  ice  chamber  overhead  to 


i66 


CLEAN  MILK 


secure  cooling  of  the  whole  wagon,  but  with  the  doors  continually 
open  the  result  in  hot  weather  is  far  from  satisfactory.* 

Three  sets  of  bottles  are  necessary  in  distributing  milk,  one 
remaining  at  the  customer's  house,  one  on  the  way  to  and  from 
the  farm,  and  the  other  at  the  farm.  Two  whole  sets  of  bottle 
boxes  are  required,  one  at  the  farm  and  the  other  passing  to 
and  fro  each  day.  The  delivery  baskets  (Fig.  50)  are  convenient 
in  carrying  bottles  from  the  wagon  to  the  customer's  house. 


Fig.  49. 


Milk  Wago 


The  matter  of  bottles  is  an  important  one.  The  loss  from  the 
customers  not  returning  empty  bottles  has  wrecked  many  enter- 
prises. The  men  on  the  delivery  wagons  should  be  required  to 
charge  patrons  for  bottles  each  day  and  credit  them  with  re- 
turned  bottles.      Those  bottles   not    returned    at   the   end   of   the 


*  These  milk  wagons  are  made  by  the  Sycamore  Wagon  Works,   Syca- 
more,   Illinois. 


HINTS  CONCERNING  DISTRIBUTION 


167 


month  are  charged  with  the  milk  on  the  bill.  Some  loss  of  this 
kind  and  from  breakage  is  unavoidable  until  the  paper  milk  bottle 
comes  into  general  use.  The  surest  way  of  escaping  loss  of  milk 
bottles,  which  is  one  of  the  most  serious  causes  of  disaster,  and  also 
loss  in  collection,  is  through  the  use  of  tickets.  Patrons  must  be 
instructed  not  to  place  milk  tickets  in  empty  milk  bottles,  as  they 
otherwise  will  invariably  do.  The  tickets  stick  to  the  bottom  of  the 
wet  bottle  and  cannot  be  readily  removed  by  the  driver  of  the  de- 
livery wagon.  If  milk  sells  for  ten  cents  a  quart  and  a  customer  be- 
gins to  take  one  quart  of  milk  daily  he  may  be  sold  a  package  of  ten 
tickets  for  one  dollar.    Then  the  first  day  two  tickets  are  withheld, 


Fig-  50. 

W\ 

'"'"    i 

Delivery  Basket.     A  heavier  pattern  is  now  sold,  made  of 
metal  strips,  and  is  more  serviceable. 

one  paying  for  the  milk  and  the  other  for  the  bottle.  If  the  bottle 
is  returned  the  following  day  and  another  bottle  of  milk  is  delivered, 
then  the  customer  gives  but  one  ticket  to  the  milkman.  But  if  the 
first  bottle  is  not  returned,  then  the  milkman  takes  two  tickets  the 
second  day  and  so  on.  Every  returned  bottle  by  a  customer  means 
that  he  receives  a  ticket  or  credit  for  a  ticket  for  each  bottle  returned. 
And  an  empty  bottle  is  regarded  of  the  same  value  as  one  quart  of 
milk.  If  for  any  reason  a  responsible  customer  is  out  of  tickets  and 
cannot  pay  for  more  at  the  moment  of  arrival  of  the  milkman,  the 
latter  gives  the  customer  a  package  of  tickets  and  requests  the  cus- 
tomer to  sign  a  regular  receipt  for  same.     A  bill  for  the  tickets 


1 68  CLEAN  MILK 

is  then  sent  at  once  through  the  mail  to  formally  notify  the  cus- 
tomer of  his  indebtedness. 

Another  method  which  has  been  employed  consists  in  the  use 
of  the  time-book,  made  to  fit  in  the  pocket,  and  which  the  man  on 
the  delivery  wagon  carries.  The  names  of  customers  in  the  account 
book  should  follow  the  same  order  as  that  observed  in  visiting  them 
on  the  milk  route.  See  page  344  for  forms  used  in  keeping  ac- 
counts. This  book  is  ruled  so  that  when  the  book  is  opened  there 
are  columns  on  each  two  pages,  facing  one  another,  for  all  the 
days  of  the  month.  The  customers'  names  are  written  down  in  a 
column  on  the  left-hand  edge  of  the  page  and  his  account  kept 
on  a  horizontal  line  extending  across  the  two  open  pages.  Two 
such  books  are  used,  the  delivery  man  having  one  on  one  day  and 
the  other  book  the  following  clay,  so  that  each  day  one  book  may 
be  turned  into  the  office  for  inspection.  On  each  day  two  of  the 
perpendicular  columns  are  used  for  each  customer.  In  the  first 
column  is  entered  the  amount  of  milk  or  cream  taken  and  in  the 
second  column  the  number  of  bottles  returned.  This  method  is  not 
so  good  as  the  preceding.  In  order  to  avoid  trouble  it  is  neces- 
sary for  every  firm  distributing  any  considerable  amount  of  milk  to 
have  a  special  man  who  shall  be  familiar  with  the  customers  on  each 
milk  route  in  case  of  sudden  failure  of  a  driver  to  attend  to  his 
duties. 

If  the  milk  is  to  be  marketed  in  the  best  possible  manner, 
especially  if  sold  for  infants'  use,  there  should  be  placed  a  parch- 
ment paper  bottle  cap  over  the  ordinary  cardboard  cap.  The  ob- 
ject of  this  extra  paper  cap,  which  is  waterproof,  is  to  prevent 
dust,  dirt,  and  water  (from  melting  ice)  containing  germs  from 
soiling  the  cap  which  directly  covers  the  milk.  In  removing  the 
latter  any  material  on  the  cap  might  easily  fall  into  the  milk.  The 
parchment  paper  caps  are  held  in  place  by  a  rubber  band  about  the 
neck  of  the  milk  bottle  and  cost  less  than  one-tenth  of  a  cent 
when  bought  in  quantity.     On  them  may  be  printed  the  day  and. 


HINTS  CONCERNING  DISTRIBUTION 


169 


month  the  milk  is  produced,  the  name  of  the  farm  and  the  fact 
that  the  milk  is  certified  by  a  certain  commission.     The  certificate 


Fig-  51- 


Philadelphia  Pedtatrle  Society 


MILK  COMMIS5 

September  10, 

Milk  fr 
ware  Co.,  Pa.,  h!  __ 
experts  of  the  Mi 
to  be  up  to  the  re 
examination  is 
and.    if    satist; 
hotties  will  be  issu 
Uo*x  the  Dates. 


ERTIFICATB. 

Dairy,  Dela- 
eaamined  by 
i  and  found 
rds.  Another 
hfn  a  month, 
labels  for  the 
ed  Oct.    10,   1907. 


Methods  of  marking  parchment  caps  for  certified  milk. 
Laboratory. ) 


(Bull.  41  Hygienic 


of  the  milk  commission  is  often  placed  between  the  cardboard  and 
parchment  caps.     The  name  of  the  producer  and  the  fat  content 

Fig.  52. 


Copper  case  in  which  caps  for  milk  bottles  are  placed  and  then  are  put  in  the 
sterilizer  for  milk  utensils.  Sterile  caps  can  be  best  handled  in  this  holder  because 
they  may  be  removed  when  wanted  for  use  by  only  touching  their  outer  edges. 


of  the  milk  or  cream  may  be  printed  on  the  parchment  or  tinfoil 
cap.    The  best  method  consists  in  covering  the  sterilized  cardboard 


170  CLEAN  MILK 

cap  with  paraffin  over  which  the  parchment  cap  is  placed.  By 
this  method  milk  is  prevented  from  leaking  and  the  cap  cannot  be 
removed,  or  the  bottle  tampered  with,  without  discovery  of  the  fact. 
The  date  on  which  the  milk  is  to  be  sold  may  be  stamped  with  a. 
rubber  stamp  on  the  paraffin  itself. 

The  appearance  of  the  men  on  the  delivery  wagon  is  of  im- 
portance. In  this  region  the  use  of  uniforms  of  khaki  in  summer 
and  corduroy  in  winter  has  proved  satisfactory. 

Clean  milk  is  of  special  value  in  feeding  babies.  For  this 
reason  endeavor  should  be  made  to  inform  the  public  of  the  exis- 
tence of  the  opportunity  to  obtain  clean  milk  by  those  selling  this 
article,  and  its  use  for  infant  feeding  should  be  made  as  easy 
as  possible. 

The  following  circular  has  been  used  for  distribution  among 
the  physicians  of  a  city  and  embodies  matter  which  they  may 
pass  on  to  their  patients : 

CERTIFIED  MILK  FOR  INFANT  FEEDING. 

The  Dairy  desires  to  call  the  attention  of  physicians  to  the  opportunity 
offered  them  for  not  only  feeding  pure  milk  to  infants,  but.  by  means  of 
analysis  of  this  milk  and  cream,  to  prescribe  an  infant  food  of  known  com- 
position. 

A  dipper  is  furnished  by  which  the  top  milk  may  be  removed  from  the 
bottle.  The  upper  9  ounces  of  the  milk  contains  approximately  13  per  cent, 
of  fat  when  thus  removed.  One  part  of  this  top-milk  with  5  parts  of  water 
gives  Fat,  2.1  per  cent.;  Proteids,  0.6.  suitable  for  feeding  infants  from  3rd 
to  14th  day  of  age.  Diluted  with  4  parts  of  water  gives  Fat,  2.6  per  cent.; 
Proteids,  o.S  per  cent.;  suitable  for  feeding  from  2nd  to  6th  week  of  age. 
Diluted  with  3  parts  of  water,  gives  Fat,  3.2  per  cent.;  Proteids,  1.0  per  cent.; 
suitable  for  feeding  from  6th  to  nth  week.  For  feeding  from  nth  week  to 
5th  month,  the  upper  pint  is  removed  with  dipper  from  the  bottle,  and  diluted 
-with  i^f  parts  of  water,  gives  Fat,  3.4  per  cent.;  Proteids,  1.45  per  cent.  The 
milk  for  feeding  from  the  5th  to  10th  month  is  obtained  by  pouring  off  the 
upper  pint  from  the  bottle  and  diluting  it  with  an  equal  quanity  of  water. 
This  gives  Fat,  4.0  per  cent. ;  Proteids,  2.0  per  cent. 

Instead  of  water,  barley  water,  lime  water  or  dextrinized  gruels  may  of 
course  be  used  as  a  diluent.  Milk  sugar  may  be  added  in  proportion  of  1 
ounce  to  20  of  the   milk  mixture. 

The  milk  is  obtained  from  tuberculin  tested  and  frequently  inspected  cows,  and 
under  the  most  cleanly  conditions  pertaining  to  the  animals,  stables  and  para- 


HINTS  CONCERNING  DISTRIBUTION 


171 


phernalia.  The  milk  is  drawn  into  covered  pails,  through  a  small  aperture 
in  the  top,  and  falls  through  sterile  cheesecloth  into  the  bottom  of  the  pail. 
It  is  immediately  aerated  and  cooled,  is  put  into  bottles  at  the  farm,  and 
kept  on  ice  until  it  reaches  the  consumer.  The  milk  contains  nearly  5  per 
cent,  butterfat  and  averages  but  2,000  to  5,000  bacteria  to  the  c.  c. 

It  will  not  be  necessary  to  pasteurize  this  milk,  and  the  modified  milk 
mixtures  above  recommended  will  be  found  much  superior  to  dirty  milk 
which  has  been  sterilized  and  modified.  The  top-milk  should  be  removed 
from  the  bottles  on  their  arrival,  and  kept  on  ice,  to  give  good  results.     This 

milk   is   subject    to    frequent    bacteriological    and    chemical   tests  by   Dr.    

and    Mr.     at    the    County    Medical    Society    Laboratory.      The    formulae 

are  taken  from  Holt,  as  recommended  by  him  for  healthy  infants,  and  the 
following  table  is  also  from  his  book: 

Schedule  for  Feeding  a  Healthy  Child  During  the  First  Nine  Months. 


1 

II 

III 

IV 

V 


Age 


2  to  14  days 

2  weeks  to  5  weeks. . . 
5  weeks  to  10  weeks.. . 
10  weeks  to  4  months. 
4  months  to  9  months. 


No.  of 

No.  of 

feedings 
in  24 
hours. 

between 
feedings 
by  day. 

night 
feedings 
(10  P.  M. 
to  7  A.  M.) 

Quantity 
for  one 
feeding. 

10 

2  hours 

2 

I-2i  oz. 

10 

2       " 

2 

2-3*    " 

8 

2*      " 

I 

3-4*    " 

7 

3      " 

I 

4-6      " 

6 

3      " 

O 

5-8      " 

Quantity 
for  24 
hours. 


15  oz. 


20-32 
24-36 
28-42 
30-48 


The  reason  for  diluting-  cow's  milk  lies  in  the  fact  that  the 
proteids  are  so  much  greater  in  amount  in  cow's  than  in  women's 
milk  (see  p.  47),  and  also  that  the  proteids  in  cow's  milk  are  less 
digestible  *  than  in  human  milk — for  babies.  Many  recent  experi- 
ments have  apparently  shown  that  this  reasoning,  which  has  been 
generally  adopted  by  physicians,  is  wrong  and  that  the  fat  in  cow's 
milk  is  the  indigestible  nutrient  for  babies.  It  is  said  that  rich  cow's 
milk  forms  large,  indigestible  curds  in  the  stomach  and  that,  even 
in  calves,  rich  cow's  milk  is  less  wholesome  than  skim  milk.  This 
latter  is  a  fact.  It  is  further  said  that  rich  cow's  milk  abstracts 
alkaline  salts  from  the  body  in  order  that  these  salts  may  saponify 
and  so  aid  digestion  of  the  fat  in  the  bowels.  And  again,  that  this 
removal  of  alkaline  salts  or  mineral  matter  is  what  brings  on  scurvy 
and  rickets  in  babies.    This  is  probably  untrue  or  but  partially  true. 

*  In  the  infant  stomach  the  curd  of  cow's  is  much  tougher  than  that  of  human 
milk. 


1/2  CLE  AX  MILK 

However,  rich  milk  is  always  diluted  in  proportion  to  the  fat  it  con- 
tains, when  properly  fed  to  infants. 

The  advocates  of  the  theory  that  cow's  proteids  are  suitable 
for  children  recommend  that  babies  be  fed  on  whole  skim  milk 
from  birth  to  the  end  of  the  first  month,  and  then  upon  whole 
cow's  milk  after  that  time — providing  the  cow's  milk  does  not 
exceed  3.5  per  cent,  in  fat-content. 

While  this  method  simplifies  feeding  of  babies,  yet  it  must  be 
appreciated  that  the  chemical  and  physical  properties  of  fat.  lactose 
and  proteids  are  different  in  cows'  and  human  milk.  Furthermore, 
actual  experience  in  the  feeding  of  young  infants  has  not  proved  that 
this  is  the  best  method,  as  both  skimmed  milk  and  whole  milk  often 
absolutely  disagree  with  babies  during  the  first  months  of  their  life. 

One  of  the  chief  difficulties  physicians  have  in  prescribing  milk 
mixtures  for  babies  is  their  ignorance  of  the  exact  composition  of 
the  milk  and  cream  which  their  patients  will  use.  The  milk  from 
the  same  herds  will  be  of  very  uniform  composition,  varying  some- 
what with  the  season,  but  hardly  enough  to  make  any  material 
.difference  in  calculations  for  infant  feeding.  The  dipper  used 
for  removing  the  cream  is  shown  in  Fig.  53,  and  is  two  and  one- 
fourth  inches  long  and  three-fourths  of  an  inch  in  diameter.  It 
holds  a  tablespoonfnl  or  one-half  an  ounce  of  milk,  and  is  used 
to  remove  any  part  of  the  top  milk  without  mixing  the  milk  with 
the  cream.  A  siphon  (Fig.  53)  is  also  furnished  customers  to 
remove  the  skim  milk  from  the  milk  bottle.  This  we  find  is  gen- 
erally employed  and  liked  by  families  who  use  cream  on  the  table, 
and  at  ten  cents  a  bottle  for  milk  containing  five  per  cent,  of  fat 
the  customers  get  as  much,  or  more,  cream  than  could  be  bought 
for  this  sum  and  have  the  skim  milk  to  use  in  cooking.  The 
siphon,  of  glass  tubing,  three-eighths  of  an  inch  outside  diameter, 
has  a  short  arm,  just  long  enough  (9^2  in.)  to  reach  to  the  very 
bottom  of  the  milk  bottle,  and  a  long  arm  five  inches  longer.  The 
siphon  is  filled  with  clean  water  by  holding  the  shorter  arm  under 


Fig-  53- 


Showing  Dipper  and  Siphon  for  Removing  Cream  and  Milk  respectively, 
(See  page  172.) 


HINTS  CONCERNING  DISTRIBUTION  173, 

a  water  faucet,  and  when  the  water  appears  at  the  end  of  the  longer 
arm  this  end  is  closed  by  the  thumb  and  the  shorter  arm  is  inserted 
to  the  bottom  of  the  bottle  and  the  thumb  released,  allowing  the 
tube  to  rest  in  the  bottle.  First  the  water  flows  out  and  then  the 
milk.  The  cream  gradually  settles  in  the  bottle  until  the  lower 
border  of  cream  touches  the  bottom  of  the  bottle,  when  the  siphon 
is  at  once  removed. 

A  method  of  distributing  clean  milk  for  infants  is  by  means 
cf  the  infant  milk  depot,  dispensary,  or  Gontte  de  Lait.  These 
were  first  established  in  the  United  States  by  Mr.  Nathan  Straus  in 
New  York  in  1893.  The  object  is  to  educate  the  poor  in  infant 
feeding;  to  supply  at  a  nominal  price  the  cleanest,  most  wholesome 
cows'  milk  in  closed  bottles  containing  one  feeding  (so  that  the 
milk  cannot  be  contaminated),  and  modified  to  suit  the  age  of 
infants.  The  stations  are  under  medical  control  and  in  the  care 
of  trained  nurses  who  instruct  mothers  in  caring  for  their  children 
and  urge  the  nursing  of  babies  when  it  is  possible.  Many  of  these 
depots  are  open  the  year  round.  In  some  depots  raw,  certified 
milk  is  used;  in  others  the  milk  is  both  certified  and  pasteurized. 
There  were  21  cities  having  such  depots  in  1907,  four  of  which  were 
supported  by  city  health  boards  and  the  rest  by  private  philanthropy. 
They  are  of  great  educational  and  life-saving  value. 


CHAPTER  IX 


MILK  INSPECTION 


THE  duties  and  tests  of  the  milk  inspector  are  divided  into 
those  performed  in  and  out  of  the  laboratory.  Out  of  the 
laboratory,  the  tests  are  mainly  those  of  the  senses.  In 
some  cities  the  collector  of  milk  samples  tests  the  milk 
for  fat  and  solids  by  the  lactoscope  and  lactometer  (see  pp.  197, 
203),  but  more  accurate  tests  may  be  made  in  the  laboratory.  A 
temperature  test  is,  however,  required  by  most  enlightened  cities, 
and  when  the  milk  is  found  to  have  a  temperature  above  500  F.  it 
is  condemned.  The  inspector,  in  taking  samples  of  milk  for  the 
laboratory,  should  thoroughly  stir  the  milk.  This  may  be  accom- 
plished by  "  stirrers."  made  like  the  dasher  of  the  old-fashioned 
dasher  churn  if  the  milk  is  in  cans  and  is  to  be  examined  chemically. 
Milk  which  is  to  be  examined  for  bacteria  should  not  be  mixed 
with  a  stirrer  or  other  contaminating  utensil.  A  special  sterile 
pipette  is  employed  by  Boards  of  Health  (see  pp.  251-3).  A  milk 
bottle  may  be  inverted  and  well  shaken  before  taking  the  sample 
with  a  sterile  pipette  or  by  pouring  it  from  the  bottle.  Milk  in  cans 
may  be  mixed  by  pouring  it  from  the  original  can  into  a  sterile 
can  and  back  again,  or  by  stirring  with  a  sterile  pipette  (see  p.  253) 
after  shaking. 

The  bottles  in  which  the  milk  is  placed  for  bacterial  examina- 
174 


I 


MILK  INSPECTION  175 

tion  are  sterilized  by  20  minutes  boiling  or  by  sterilizing  in  a  ster- 
ilizer. 

The  corks  should  be  sterilized  in  the  same  manner.  The  bottle 
must  be  filled  to  the  cork  and  packed  in  a  vessel  with  enough  ice 
to  last  till  the  examination  is  made. 

If  a  sample  of  milk  is  taken  for  chemical  examination  only, 
the  milk  is  mixed  by  pouring  it  from  one  bottle  or  can  to  another. 

In  some  cities  the  original  bottle  is  taken  for  chemical  exam- 
ination (this  is  best  in  testing  certified  milk),  but  this  is  expen- 
sive because  the  inspector  is  encumbered  with  unnecessary  weight 
and  there  is  loss  of  milk  and  bottle  to  the  owner,  or  to  the  city, 
in  case  the  milk  is  paid  for.  The  two  chief  reasons  for  agitating 
the  milk  are  to  thoroughly  mix  the  cream  for  determining  the  fat, 
and,  again,  to  estimate  by  a  bacteriological  test  the  number  of  germs. 
In  the  latter  case  it 'is  especially  important,  as  ninety-nine  per  cent. 
of  the  germs  in  milk  become  entangled  in  the  cream.  Two  ounces 
•of  milk  are  sufficient  for  a  fat  or  bacteriological  test,  and  four 
ounces  for  a  test  for  preservatives.  The  inspector  seals  the  corks 
of  the  bottle,  and,  also,  should  place  some  sealing  wax  on  the 
edge  of  the  label,  as  the  labels  are  often  soaked  off  and  placed 
on  a  similar  sealed  bottle.  This  happens  where  the  inspector 
is  required  to  give  a  duplicate  sealed  sample  to  the  milkman;  and 
the  milkman,  when  he  knows  his  sample  is  adulterated,  may  get  a 
sealed  bottle  given  to  another  milkman  (which  contains  pure  milk) 
and  take  the  label  from  the  adulterated  sample  and  place  it  on  the 
pure  sample.  He  then  brings  the  pure  sample  into  court  with  the 
label  number  the  inspector  placed  on  his  adulterated  sample  and  in 
a  bottle  with  an  unbroken  official  seal  on  the  cork.  For  full  direc- 
tions for  taking  samples  for  bacterial  analysis,  see  p.  251. 

Milk  may  be  condemned  on  account  of  visible  dirt.  This  is 
ascertained  by  straining  milk  from  one  can  to  another  through 
cheesecloth,  or  by  straining  only  the  bottom  portions  of  several 


1 76  CLEAN  MILK 

cans.*  In  Dresden  there  is  a  legal  standard  requiring  that  the  dry- 
dirt  in  milk  shall  not  exceed  8  milligrammes  to  the  litre  (about 
yi  grain  to  the  quart).  The  taste  may  be  bad,  as  from  the  odor 
of  manure,  or  from  improper  feeding,  or  disease  (mastitis)  of  the 
cows,  and  may  suffice  to  condemn  the  milk.  The  color  may  be  un- 
usual, as  when  the  cream  is  highly  colored  on  milk  which  has  been 
obtained  from  cows  recently  calved.  Curdling  of  the  milk  on  boil- 
ing will  occur  if  the  sample  is  colostrum.  The  brilliantly  colored 
milks,  caused  by  special  bacteria,  are  seldom  seen  in  this  country. 
The  odor  of  milk  may  be  bad  from  various  causes,  as  from  improper 
feeding  of  the  cows,  manure  in  the  milk,  or  from  the  milk  re- 
maining a  long  while  in  dirty  barns.  Sour  milk  may  be  con- 
demned. Slimy  or  stringy  milk  are  not  rfncommon,  but  are  gener- 
ally only  noticeable  several  hours  after  milking,  and  so  usually  escape 
attention  until  in  the  consumer's  hands.  The  existence  of  garget 
in  cows  may  produce  slimy  or  stringy  milk;  also  it  occurs  in  the 
milk  of  cows  which  have  been  milked  late  in  the  period  of  lactation; 
certain  herbs  are  said  to  cause  it.  It  is  somewhat  doubtful  whether 
the  condition  is  always  due  to  a  special  germ  (B.  lactis  viscosus; 
see  p.  28)  or  whether  it  is  caused,  at  times,  by  chemical  substances 
(ferments)  which  occur  in  certain  plants  (Pinguicula).  Fishy  milk 
is  caused  by  rusty  cans,  and  cows  inhabiting  pastures  containing 
stagnant  pools  of  water  may  yield  milk  with  this  odor  or  taste. 

A  General  Outline  of  a  Scheme  for  the  Control,  Supervision 
and  Inspection  of  a  City  Milk  Supply 

The  legal  control  of  a  city  milk  supply  is  in  the  hands  of  the 
City  Board  of  Health.  The  State  Board  of  Health  should,  however, 
work  in  cooperation  with  the  City  Board  through  its  jurisdiction 
over  the  territory  from  which  the  milk  is  obtained.  When  the  milk 
is  drawn  from  several  states  this  is,  of  course,  of  but  slight  value. 
Moreover,  state  supervision  is  not  essential,  since  the  city  authorities 

*  For  accurate  estimation,  see  p.  305. 


MILK  INSPECTION  177 

can  bring  to  bear  sufficient  influence  over  the  producer  of  unsanitary 
milk  in  the  following  ways :  By  condemning  such  when  it  arrives 
in  the  city;  by  warning  or  fines;  by  revoking  the  license  of  the 
dealer  in  the  same  in  the  city;  and  by  requiring  that  the  premises 
on  which  the  milk  is  produced  be  inspected  before  the  milk  can  be 
sold  in  the  city. 

Supervision  of  a  milk  supply  must  begin  at  the  barn  and  be 
continued  until  the  milk  reaches  the  consumer.  Thus  milk  must  be 
inspected  at  the  following  points : 

1.  At  the  farm. 

2.  During  transportation  from  the  farm  to  the  R.  R.  or 
creamery. 

3.  At  the  creamery,  when  this  is  the  shipping  point. 

4.  On  the  cars  during  transportation  to  the  city. 
'5.     At  the  city  R.  R.  or  receiving  station. 

6.  On  the  wagon  in  the  city. 

7.  At  the  city  dairy,  hotel,  restaurant,  retail  store  and  home 
of  the  consumer. 

The  country  furnishing  milk  must  be  mapped,  the  farms  and 
creameries  from  which  milk  is  shipped  must  be  plotted,  and  the 
territory  divided  into  districts,  each  under  the  supervision  of  an 
inspector  living  in  the  region.  It  has  been  recommended  that  there 
be  one  inspector  to  each  100  farms.  At  present  New  York  City  has 
about  100  inspectors  (1907)  to  supervise  some  thirty  to  forty  thou- 
sand farms  in  six  states  and  shipping  milk  into  the  city  from  points 
four  hundred  miles  distant.  No  milk  should  be  permitted  to  enter 
a  city  until  the  seal  of  inspection  has  been  first  placed  upon  it  by  an 
inspector  in  the  country. 

When  milk  is  shipped  from  creameries  or  country  receiving 
stations  these  form  convenient  points  for  inspection  and  also  serve 
as  a  base  for  investigation  of  the  farms  supplying  the  creameries. 
At  the  creameries  the  following  demand  looking  into  :  ( 1 )  The 
cleaning  and  sterilization  of  all  utensils;  (2)  the  water  supply  and 


1 78  CLEAN  MILK 

drainage;  (3)  the  temperature  at  which  milk  and  cream  are  kept; 
(4)  general  cleanliness,  requiring  the  absence  of  flies  and  dust. 

Inspection  of  farms  is  by  far  the  most  valuable  of  all  in- 
spections relating  to  milk.  Laboratory  examinations  in  the  city 
will  not  take  its  place.  Laboratory  examinations  will  not  dis- 
cover any  of  the  special  germs  most  dangerous  to  man,  as  those 
of  tuberculosis,  typhoid  and  scarlet  fever  and  diphtheria,  or  those 
derived  from  diseases  of  the  cow — that  is  the  usual  routine  exam- 
ination. Hence  regular  veterinary  inspection  is  indispensable. 
Cows  suffering  from  disease  of  the  udder,  as  from  the  common 
forms  (colon  bacillus,  streptococcus,  or  staphylococcus,  B.  necroph- 
orous  infection)  of  mastitis,  or  tuberculosis,  actinomycosis,  or  bo- 
trvomycosi^of  the  udder;  or  from  septic  metritis,  parturient  apop- 
lexy, retained  after  birth,  vaginal  discharge,  gastroenteritis,  diar- 
rhea, constipation,  suppurating  lesions,  foot  rot,  necrosis,  tetanus, 
fever,  mange,  or  any  severe  constitutional  disease,  or  cows  recently 
with  calf  or  about  to  calve,  should  be  debarred  from  supplying 
market  milk  and  the  sick  animal  should  be  removed  from  the  barn 
in  most  cases.  Not  only  this  but  if  any  contagious  disease  exists 
among  cows,  as  tuberculosis,  foot  and  mouth  disease,  black  quar- 
ter, cow  pox,  milk  sickness,  anthrax,  lung  plague,  septic  en- 
teritis or  mastitis,  or  septicemia  or  rabies — the  milk  of  the  whole 
herd  should  be  refused  and,  after  the  disease  is  past  or  the  cows  re- 
moved, the  premises  must  be  thoroughly  disinfected  (see  p.  346). 

It  is  wiser  that  all  inspectors  of  farms  should  be  veterinarians 
and  they  should  have  had  previous  training  in  the  production  and 
handling  of  clean  milk.  Some  authorities  state  that  half  the  farm 
inspectors  should  be  veterinarians  and  the  rest  trained  dairy  in- 
spectors. The  frequency  of  examination  of  farms  depends  upon  the 
results  of  bacteriological  examinations  of  milk.  The  farms  supply- 
ing the  dirtiest  milk  need  the  more  frequent  inspections.  In- 
spections should  be  made  once  a  month  if  possible.  Certified  milk 
farms  should  be  inspected  weekly.  The  veterinary  inspector  must 
rely  partly  on  the  information  given  him  as  well  as  upon  his  obser- 


MILK  INSPECTION  179 

nation.  Thus  he  cannot  examine  all  occupants  of  the  farm  for 
contagious  disease,  as  he  is  neither  empowered  nor  competent  to 
do  so.  Again  he  may  not  be  able  to  be  present  at  milking  time, 
although  this  is  almost  essential  to  make  a  proper  inspection.  The 
form  on  which  the  inspection  is  written  (see  pp.  209,  210)  will  be 
made  in  quadruplicate,  i.  e.,  the  original  and  3  carbon  copies.  One  is 
to  be  retained,  one  is  sent  at  once  to  the  city  health  office,  one  to 
the  city  retailer,  and  one  is  given  to  the  farmer.  The  standard  of 
marking  the  inspection  blank  is  of  importance.  Thus  Health  Officer 
Woodward  says  that  if  the  standard  is  perfection,  a  total  per- 
centage of  30  should  enable  a  farm  to  pass  muster;  but,  if  the 
standard  is  only  one  which  might  be  reasonably  expected  of  the 
present-day,  progressive  dairyman,  then  a  total  of  70%  should  be 
required. 

If  the  farm  is  not  up  to  the  standard  the  inspector  must  notify 
the  farmer  that  he  will  take  his  permit  away  (see  p.  208)  if  the 
requirements  are  not  fulfilled.  If  the  farmer  is  outside  of  the 
legal  authority  of  the  inspector  then  the  city  dealer  in  the  milk 
will  be  notified  by  the  inspector,  through  the  city  health  office, 
that  his  permit  will  be  revoked  unless  he  ceases  to  purchase  the 
milk  from  the  delinquent  farmer. 

It  is  usually  the  custom  to  give  the  producer  fair  warning  and 
an  opportunity  to  repair  his  shortcomings  rather  than  to  imme- 
diately invoke  the  aid  of  the  law.  If  the  milk  is  subject  to  in- 
fection from  contagious  disease  its  sale  will  be  at  once  stopped  by 
the  inspector.  I  quote  the  following  from  Dr.  Woodward  of  Dis- 
trict of  Columbia,  to  whom  I  am  much  indebted  for  information 
concerning  milk  inspection  :  * 

"  Each  inspector  of  dairy  farms  files  with  the  health  officer, 
daily,  a  report  of  his  operations  for  the  preceding  day.  In  addition 
to  this  he  keeps  his  own  record  of  outstanding  notices,  and  as  soon 


*  See  Bull.  No.  41,  Hygienic  Laboratory,  U.  S.  Surgeon-General's  office. 


180  CLEAN  MILK 

ss  practicable  after  the  expiration  of  the  time  allowed  for  the  cor- 
rection of  objectionable  conditions,  he  visits  the  premises  to  see- 
whether  the  notice  has  or  has  not  been  complied  with.  If  it  has 
been,  the  inspector  makes  report  accordingly.  If  it  has  not,  he  takes 
action  to  enforce  compliance.  He  may  immediately  serve  a  notice 
requiring  the  licensee  to  show  cause,  satisfactory  to  the  health 
officer,  why  his  permit  (to  ship  milk)  should  not  be  canceled.  Or 
he  may  recommend  that  a  letter  of  that  purport  be  written  by  the 
health  officer.  Or,  if  the  farm  be  located  in  the  District,  he  may 
recommend  immediate  prosecution  in  the  police  court,  and  with  the 
approval  of  the  health  officer  he  may  institute  such  prosecution. 
If  a  licensee  has  been  notified  to  show  cause  why  his  permit  should 
not  be  canceled,  and  has  failed  to  do  so,  or  has  shown  no  sufficient 
cause,  then  the  health  officer  cancels  the  permit  and  notifies  the 
licensee  and  his  consignee  or  retailer,  if  he  have  one,  that  such 
action  has  been  taken.  If  thereafter  the  milk  from  that  farm  is 
brought  into  the  District  the  person  at  whose  instance  it  is  brought 
is  prosecuted  in  the  police  court." 

The  farms  need  inspection  in  regard  to  the  ensuing  matters : 

Cows. 

i.  Whether  tested  with  tuberculin. 

2.  Cleanliness. 

3.  Whether  affected  with  udder  or  other  disease.     Isolation 

of  diseased  animals. 

4.  Amount  of  exercise. 

5.  Food.     Kind  and  time  of  feeding. 

Barn. 

1.  Cleanliness. 

2.  Ventilation. 

3.  Light. 

4.  Removal  of  manure. 

5.  Drainage  and  cleanliness  of  surroundings. 

6.  Use  of  small-top  milk  pail. 


MILK  INSPECTION  l8r 

Methods  of  Milking. 

i.     Health,  cleanliness  and  clothing  of  milkers. 

Milk  Rooms. 

i.     Cleanliness  of  premises.     Presence  of  dust  or  flies. 

2.  Health  and  cleanliness  of  employees. 

3.  Purity  of  water  and  ice  supply. 

4.  Method  of  cooling  milk. 

'5.     Method  of  keeping  and  storing  milk. 

6.  Method  of  washing  and  sterilizing  utensils  and  care  of 

the  clean  utensils. 

7.  Method  of  filling  bottles  or  cans. 

Transportation. 

1.  Care  and  cooling  of  milk  on  wagons,  at  station  or  cream- 

ery, on  railway,  and  at  receiving  station. 

2.  Washing  of  returned  empty  utensils. 

Insistence  should  be  gradually  made  that  cows  supplying- 
market  milk  should  be  tuberculin-tested.  Now  Grand  Rapids, 
Mich.,  Minneapolis,  Montclair,  N.  J.,  Colorado  Springs  and  Pasa- 
dena are  supplied  with  milk  from  tuberculin-tested  cows. 

Dr.  Goler,  of  Rochester,  N.  Y.,  also  recommends,  in  case 
the  territory  supplying  a  city  is  large,  the  establishment  of  one  or 
more  laboratories  in  the  country  as  sub-stations  for  the  work  of 
milk  inspection.  This  might  be  conveniently  carried  out  in  con- 
nection with  creameries. 

Country  inspectors  should  not  only  perform  their  police  duties, 
but  should  act  as  teachers  and  should  talk,  and  distribute  printed! 
matter,  concerning  everything  which  relates  to  the  production  and. 
care  of  sanitary  milk. 

The  plan  adopted  by  the  Massachusetts  Board  of  Health,  in 
publishing  a  monthly  list  of  well  conducted  and  cleanly  farms,  is  to 


182  CLEAN  MILK 

be  recommended.  Goler  urges  the  establishment  of  model  dairy 
farms  by  the  state  in  connection  with  the  laboratory  substations 
in  the  country,  the  scheme  comprising  the  remodeling  of  some  old 
and  run-down  farm,  so  that  in  its  upbuilding  the  farmer  could 
apply  the  same  measures  to  his  own  premises. 

In  regard  to  the  transporting  of  milk  on  the  railroad — railways 
carrying  milk  to  the  large  cities  of  the  country  now  supply  refriger- 
ator cars  for  milk,  with  adequate  icing  facilities  to  cool  milk  below 
500  F.,  in  most  cases.  When  such  refrigerating  arrangements  are 
not  obtainable,  milk  and  cream  should  be  shipped  as  advised  on 
p.  123. 

Inspection  on  the  cars  is  limited  to  taking  the  temperature  of 
milk.  At  the  receiving  station  in  the  city  there  must  be  daily 
inspection  with  reference  to  the  temperature  of  milk,  to  the  care 
of  cans  and  bottles  of  milk  while  en  route,  and  to  the  condition 
of  empty  bottles  and  cans  which  are  being  returned.  The  in- 
spector shall  here  examine  milk  by  sight,  smell  and  taste  (see  p. 
176),  and  by  lactometer  and  lactoscope  (if  such  be  the  custom) , 
and  take  samples  for  laboratory  examination.  According  to 
the  writer's  views,  the  only  accurate  testing  which  should  be  clone 
by  the  collectors  of  samples  is  that  of  temperature  taking.  Testing 
for  the  solids  and  fat  and  for  adulteration  and  bacterial  content  can 
be  done  much  more  accurately  at  the  laboratory. 

During  distribution  of  milk  by  wagon  in  the  city,  inspection  is 
desirable  to  ascertain  that  the  milk  is  properly  iced  in  warm  weather, 
that  the  temperature  of  the  milk  is  kept  below  500  F.,  that  bottling 
of  milk  is  not  clone  on  the  wagon,  and  that  general  cleanliness  of 
utensils  and  wagon  is  observed.  Samples  of  milk  should  be  taken 
from  each  wagon  at  least  once  a  month  for  laboratory  examina- 
tion. 

A  sample  of  milk  should  be  taken  from  each  retail  store  every 
month.  Milk  in  the  various  stages  of  transportation  from  cow 
to  consumer  becomes  more  germ-laden  through  age  and  handling. 


MILK  INSPECTION  183 

especially  when  poured  from  one  utensil  to  another,  and  the  case 
of  the  retail  shop  is  the  worst.  This  has  been  strikingly  shown  by 
Prof.  J.  O.  Jordan,  of  Boston.  The  legal  limit  for  bacterial  con- 
tent in  Boston  is  500,000  germs  to  the  c.  c.  The  milk  during  1906, 
in  respect  to  this  standard,  was  found  to  be  distributed  as  follows: 
On  the  cars,  on  arrival,  90  per  cent,  fulfilled  the  requirements  of  the 
germ  standard  («".  c,  containing  less  than  500,000  bacteria)  ;  on 
the  wagons,  50  per  cent,  complied  with  the  germ  standard ;  and  in 
the  retail  stores,  only  18  per  cent,  complied  with  the  germ 
standard.  Such  a  difference  between  the  quality  of  milk  on  arrival 
and  subsequently  does  not  occur  in  milk  bottled  at  the  farm,  cooled 
immediately  below  500  F.  and  kept  at  that  point  all  the  time  until 
it  reaches  the  store  customer.  Only  bottled  milk  should  be  sold  in 
stores,  and  the  bottling  should  be  done  at  the  farm,  or,  less  favor- 
ably, at  the  creamery  or  city  dairy.  Inspection  at  stores  must  en- 
force requirements  for  a  proper  refrigerator  and  cooling  of  the 
milk,  and  also  that  the  store  be  apart  from  dwelling-rooms. 

Infectious  disease  in  the  person  of  workers  in  farms,  dairies, 
milk  shops  or  stores  selling  milk,  or  in  the  person  of  anyone  living 
on  the  premises,  should  lead  the  inspector  to  close  any  shop  for 
the  sale  of  milk  until  such  time  as  the  infection  is  past  and  dis- 
infection done.  Any  person  suffering  from  infectious  disease — or 
having  had  contact  with  a  patient  having  such — should  not  be 
permitted  to  handle  milk  in  a  city  dairy  or  other  place  where  milk 
is  kept  or  offered  for  sale. 

In  the  inspection  of  city  dairies,  stores,  hotels  and  restaurants, 
the  proper  cleaning  of  empty  cans  and  bottles  should  receive  special 
attention.  In  many  cities  an  ordinance  requires  that  milk  cans  and 
bottles  must  be  thoroughly  cleaned  or  sterilized  before  their  return 
to  the  farm  or  creamery.  Also  an  ordinance  should  forbid  using 
utensils  employed  for  transporting  milk  and  cream  as  receptacles  for 
any  other  material  whatsoever.     Jordan  notes  that  broken  eggs, 


1 84  CLEAN  MILK 

coffee,  oil,  chocolate,  molasses,  blood,  and,  above  all,  kerosene,  are 
not  infrequently  discovered  in  milk  cans. 

At  each  city  dairy  the  cleanliness  of  premises  and  milk  utensils, 
the  purity  of  the  water  supply,  and  the  facilities  and  method  of 
cooling  milk  and  cream  should  be  the  subjects  of  inspection. 
Samples  of  milk  should  be  taken  from  the  city  dairy  at  least  once 
monthly. 

Contact  of  the  human  body  with  milk  always  opens  up  an 
opportunity  for  the  transmission  of  typhoid,  diphtheria  and  scarla- 
tina organisms  to  milk.  This  danger  is  most  real  in  milk-tasting 
by  those  sampling  cans  through  dipping  of  the  fingers,  licking  the 
stoppers  or  in  the  use  of  spoons.  Tasting  should  only  be  done  by 
means  of  sterile  utensils  and  to  best  advantage  by  those  of  paper, 
cardboard  or  wood,  which  should  be  discarded  after  a  single  use. 
Other  utensils-1- as  spoons — should  be  washed  and  boiled  after  a 
single  use  before  being  used  a  second  time.  In  the  handling  of 
milk  the  hands  must  be  dry  and  clean,  to  avoid  any  dripping  from 
the  hands  into  the  milk. 

Regulations  embodying  such  requirements  are  now  a  part  of 
the  rules  enforced  by  some  municipal  Boards  of  Health  and  are 
essential. 

In  the  inspection  of  city  dairies,  or  places  where  milk  is  handled 
and  sold  in  the  city,  the  force  may  both  inspect  and  collect  samples; 
or  part  of  the  force  may  inspect  and  part  collect  samples. 

The  law  is  enforced  by  giving  delinquents  notice  (see  p.  208) 
to  show  why  their  permit  should  not  be  revoked.  A  copy  of  this 
permit  is  retained  and  another  sent  to  the  health  office.  In  some 
cases  of  flagrant  disregard  of  the  law  the  inspector  may  begin 
action  at  once. 

A  score  card  for  city  dairies  (see  p.  211)  is  used  by  the  in- 
spector. 

One  copy  is  given  the  owner  and  one  is  filed  in  a  compart- 
ment used  for  all  papers  pertaining  to  the  same  dairy.    On  the  score 


MILK  INSPECTION  185 

card  the  inspector  should  state  that  all  requirements  have  been 
complied  with,  or  that  proper  steps  have  been  taken  to  correct 
unlawful  conditions. 

A  form  for  the  collector  of  samples  and  chemist  is  also  sub- 
mitted (see  p.  215).  In  taking  samples,  one. is  given  to  the  vendor 
(see  p.  175)  and  one  is  immediately  analyzed  in  the  laboratory.  If 
found  below  the  standard,  prosecution  is  begun  by  the  analyst. 
The  collector  identifies  the  sample  and  the  chemist  or  bacteriologist 
testifies  to  its  composition  and  bacterial  content. 

Results  of  laboratory  findings  are  kept  in  a  card  catalogue. 
If  the  legal  standard  requires  3.5%  butter  fat,  the  inspector 
may  use  some  discretion  in  prosecuting  a  delinquent  on  the  first 
offense.  Various  justifiable  reasons  may  exist  for  a  low  butter- 
fat  content,  as  insufficient  mixing  of  the  milk,  or  breed  of  cows. 
Prosecution  may  be  at  once  begun  if  the  fat-content  falls  below 
3.25%,  or  if  the  milk  is  watered,  artificially  colored,  or  contains 
preservatives. 

In  regard  to  contagious  disease  in  its  relation  to  milk  in- 
spection. The  health  office  may  be  supplied  with  information  as  to 
any  relation  between  contagious  disorders  and  milk  supply  if  phys- 
ician's reports  are  required  to  contain  the  names  of  milkmen 
supplying  milk  to  patients  prior  to  their  sickness.  Or,  in  some 
cities,  the  milk  inspector  gets  this  information  for  the  health  office 
by  visiting  the  premises  of  all  reported  infections.  The  health 
office  should  then  serve  a  notice  on  the  dairyman  not  to  supply 
any  more  milk  in  bottles  to  the  infected  premises  until  quarantine 
is  raised.  Milk  may  be  left  in  some  utensil  supplied  by  the  owner 
of  the  premises  but  no  return  milk  utensil  must  be  taken  by  the 
milkman.  Again,  if  there  is  a  suspicious  number  of  cases  of  con- 
tagious disease  on  the  route  of  any  one  milkman,  the  health  office 
should  proceed  to  investigate  the  sources  of  the  milk  supply  and 
health  of  those  handling  the  milk.  The  veterinary  inspector  should 
conduct  this  work  in  the  country,  and  the  contagious-service,  health. 


186  CLEAN  MILK 

officer  in  the  city.  If  it  is  found  that  the  milk  is  exposed  to  in- 
fection, its  sale  should  be  at  once  stopped,  unless  the  source  of 
infection  can  be  immediately  removed. 

Inspection  of  milk  at  hotels  and  restaurants  should  be  directed 
toward  enforcing  the  ordinances  as  regards  temperature  of  milk, 
cleanliness  of  utensils  and  the  sale  of  skim  milk.  Samples  should 
be  taken  once  a  month  from  hotels  and  restaurants. 

The  proper  care  of  milk  after  it  has  reached  the  consumer  is 
the  most  difficult  matter  of  control  and  can  only  be  managed  by 
general  education  of  the  public.  The  Board  of  Health,  through  its 
monthly  bulletins,  and  those  selling  clean  milk  may  supply  the  public 
with  information  on  the  subject,  and  consumers  should  be  fined  for 
not  returning  empty  milk  bottles  or  cans  properly  cleaned. 

In  Boston  the  wholesale  milk  dealers  are  exceptionally  progress- 
ive. They  assist  the  health  authorities  by  taking  the  temperature 
of  milk  consigned  to  them,  by  straining  milk  to  discover  dirt,  by 
cleaning  empty  cans;  while  six  dealers  (1907)  have  actually  in- 
stalled bacteriological  laboratories  for  their  own  use  (Jordan). 

A  sufficient  number  of  inspectors  or  collectors  of  samples  in 
cities  may  require  one  to  each  50,000  of  population.  In  addition 
to  the  duties  described  above,  the  city  inspector  should  examine  the 
premises  of  applicants  for  a  city  license  to  sell  milk,  before  one  may 
be  issued. 

The  City  Board  of  Health  should  publish  in  a  monthly  report 
the  names  of  each  dairyman,  dividing  them  into  four  categories: 
those  selling  Certified,  Inspected,  Ordinary  Market  and  Pasteur- 
ized milk ;  and  should  report  the  number  of  bacteria  in  each.  Also 
notice  of  any  dairyman  who  has  been  found  guilty  of  infractions 
of  any  of  the  ordinances  pertaining  to  milk  should  be  thus  publicly 
announced. 

A.  D.  Melvin,  Chief  of  the  Bureau  of  Animal  Industry,  sug- 
gests that  the  following  division  be  made  of  the  milk  composing  a 
city  supply:     1.     Certified  milk.     2.     Inspected  milk  from  tuber- 


MILK  INSPECTION  187 

culin-tested  cows  housed,  fed  and  milked  under  good  conditions 
with  a  maximum  content  of  100,000  germs  per  c.c.  the  year 
round,  and  shipped  in  sterilized  containers  at  the  farm  at  a  tem- 
perature below  500  F.  3.  All  other  milk  should  be  pasteurized 
(as  soon  as  practicable  after  milking,  from  10  to  40  minutes  accord- 
ing to  the  temperature,  see  p.  218),  cooled  immediately  to  450  F., 
and  sold  at  a  temperature  below  500  F.  Clarification,  and  pasteur- 
ization should  be  done  at  a  central  plant  in  sterile,  closed  vessels, 
preferably  the  final  containers,  and  under  the  personal  supervision 
of  a  health  officer.  It  will  be  a  long  time  before  proper  pasteur- 
ization is  accomplished  in  most  cities  and  until  such  time  is  come 
it  will  be  much  wiser  for  persons  to  pasteurize  their  own  milk 
supply  at  home  (see  p.  13).  It  should  be  required  by  law  that 
pasteurized  milk  be  marked  with  labels  stating  precisely  the  date  and 
degree  of  temperature  at  which  the  milk  was  heated  and  the  time 
during  which  the  milk  was  kept  at  the  given  temperature.  In  New 
York  City  a  permit  to  sell  pasteurized  milk  is  necessary  under  the 
following  requirements :  After  pasteurization  the  milk  must  be  at 
once  cooled  and  placed  in  sterile,  sealed  containers  plainly  labeled 
*(  pasteurized,"  and  so  delivered  to  the  consumer.  The  labels  must 
bear  the  permit  number^  the  date  and  hour  when  pasteurization  was. 
completed,  the  degree  of  heat  employed  and  the  time  exposed  to  the 
heat.  Pasteurized,  milk  must  be  delivered  within  24  hours  of  the 
pasteurization  and  no  milk  shall  be  pasteurized  a  second  time.  For 
more  precise  municipal  requirements  for  pasteurized  milk,  see  p 
216). 

Milk  which  is  only  fit  for  pasteurization  should  also  be  clari- 
fied (previous  to  pasteurization)  by  passing  it  through  a  separator, 
moving  at  low  speed,  to  remove  the  dirt  and  so  improve  the  flavor 
and  appearance  of  the  milk  (see  p.  56). 

Skim  milk,  buttermilk,  and  cream  should  be  labeled  as  such, 
and  the  percentage  of  fat  in  cream  should  be  stated  on  the  label 
and  also  whether  it  is  pasteurized  (as  in  the  case  of  milk). 


CLEAN  MILK 


Milk  Preservatives 


The  most  commonly  used  preservatives  are  formaldehyde, 
borax  and  boric  acid.  Occasionally  salicylic  acid  and  sodium  car- 
bonate are  employed.  Formaldehyde  may  be  detected,  during  the 
process  of  determining  fat  by  the  Babcock  test,  by  observing  the 
color  of  the  line  of  contact  of  the  acid  with  the  milk.  When  pure 
milk  is  used  for  the  Babcock  test,  the  color  of  this  line  is  dirty 
brown,  but,  when  formaldehyde  is  present  in  the  milk,  a  distinct 
purple  hue  will  appear  at  the  junction  of  the  acid  and  milk. 

This  test  may  be  applied  in  other  ways  by  using  a  separate 
sample  of  milk.  Place  about  20  cubic  centimeters  *  of  milk  in 
a  small  glass  vessel,  dilute  with  an  equal  volume  of  water,  and 
add  commercial  sulphuric  acid,  allowing  it  to  flow  slowly  down 
the  inside  of  the  vessel.  If  formaldehyde  is  present  the  purple 
color  will  appear  at  the  junction  of  the  acid  and  milk. 

Boric  acid  or  borax  are  detected  by  adding  to  a  few  drops  of 
milk,  contained  in  a  white  dish,  a  drop  or  two  of  hydrochloric  acid, 
and  then  several  drops  of  a  saturated  alcoholic  solution  of  turmeric. 
Heat  the  dish  gently  for  a  few  minutes  and,  if  boric  acid  or  borax 
are  present,  a  pink  or  dark  red  color  will  appear.  Cool,  and  add 
a  drop  of  ammonia,  when  a  dark  blue-green  should  be  seen. 

Sodium  carbonate  is  detected  by  adding  to  the  suspected 
sample  of  milk  an  equal  volume  of  alcohol  and  then  two  drops 
of  a  one  c/o  solution  of  rosolic  acid.  If  sodium  carbonate  is 
present  a  red-rose  color  will  appear.  The  test  may  be  performed 
with  more  certainty  if  a  comparison  test  is  made  with  a  sample 
of  milk  known  to  be  pure. 

Salicylic  acid  is  rarely  used,  but  may  be  detected  by  adding  a 
few  drops  of  sulphuric  acid  to  a  small  quantity  of  milk  and  then 

*A  cubic  centimeter  (metric  system)  is  a  volume  of  fluid  equal  to  16 
drops  of  water.  Any  apothecary  can  prepare  the  substance  required  to  make 
the  above  tests  and  at  the  same  time  could  perform  the  tests  with  the  assist- 
ance of  the  description  given  above  and  show  the  farmer  or  dairyman  how 
to  perform  them  himself. 


MILK  INSPECTION  189* 

shaking  gently  with  a  mixture  of  ether  and  petrolic  ether.  The 
mixture  is  made  of  equal  parts  of  ether  and  petrolic  ether  and 
equal  volumes  of  acidulated  milk  and  ether  mixture  are  taken. 
Then,  after  standing  for  several  hours,  the  upper  ethereal  solution- 
is poured  off  and  the  remaining  liquid  is  evaporated  in  a  porcelaim 
evaporating  dish.  Add,  to  the  residue  on  the  white  evaporating 
dish,  a  few  drops  of  water  and,  if  salicylic  acid  is  present,  a  drop  of 
ferric  chloride  solution  will  produce  a  violet  or  purple  color  on  being 
added  to  the  solution. 

It  sometimes  happens  that  it  is  desirable  to  determine  whether 
milk  has  been  heated  to  1760  F.  or  over.  To  test  this  (Storch's 
test),  add  to  5  cubic  centimeters  of  milk  2  drops  of  a  freshly  pre- 
pared 2  per  cent,  solution  of  Paraphenylenediamine  hydrochloride 
or  meta-di-amido-benzene  chloride,  and  then  one  drop  of  a  2  per 
cent,  solution  of  hydrogen  peroxide.  Unheated  milk  gives  a  blue 
color  when  thus  treated,  but  milk  heated  to  1760  F.,  or  over,  gives 
no  color.*  This  test  depends  upon  the  action  of  the  ferments  or 
peroxidases,  normally  present  in  milk,  inducing  oxidation  of  meta- 
di-amido-benzene  by  means  of  hydrogen  dioxide  with  the  production 
of  a  blue  color. 

When  milk  is  heated  to,  or  over  (8o°  C.)  1760  F.,  the  ferments 
are  killed  and  the  blue  color  is  absent. 

According  to  different  authorities  the  temperature  of  the  milk, 
at  which  the  blue  color  disappears,  varies  from  75  °  C.  (1760  F.) 
for  2  minutes  (Storch),  to  8o°  C.  (see  p.  216). 

The  simplest  test  for  preservatives  is  to  place  some  milk  in  a- 
warm  place  (at  temperature  of  8o°  to  900  F.)  in  a  corked,  clean 
bottle  for  24  hours.-  If  it  does  not  sour  or  curdle,  the  addition  of 
a  preservative  may  properly  be  suspected,  unless  the  milk  has  been 

*  If  the  milk  at  once  becomes  indigo  bine,  or  the  whey  violet  or  reddish  brown, 
then  the  milk  has  not  been  heated — or  not  heated  above  172. 50  F.  If  the  milk 
turns  bluish  gray  immediately,  or  within  one-half  minute,  it  has  been  heated  to 
174. 20  F.  The  test  should  be  done  on  an  unheated  specimen  along  with  that  on 
the  suspected  sample. 


i9o  CLEAN  MILK 

pasteurized.  The  tests  described  on  pp.  188-9  may  tnen  be  tried  to 
determine  positively  the  presence  or  absence  of  preservatives. 

For  testing  the  acidity  of  milk,  an  alkali  and  phenolphthalein 
are  commonly  employed.  The  basis  of  this  test  rests  on  the  fact 
that  phenolphthalein  turns  pink  in  the  presence  of  an  alkali  and 
is  colorless  in  the  presence  of  acid.  Therefore  in  the  tests,  by 
adding  a  known  quantity  of  alkali  to  a  known  quantity  of  milk 
and  phenolphthalein,  we  may  know  just  how  much  acidity  is  present 
in  the  milk.  For  when  enough  alkali  has  been  added  to  the  milk 
and  phenolphthalein  to  turn  the  mixture  pink,  we  know  that  all 
the  acid  in  the  milk  has  been  neutralized  and  the  mixture  is  becom- 
ing alkaline. 

Roughly  speaking,  increased  acidity  in  milk  means  increase 
in  number  of  lactic  acid  bacilli.  The  degree  of  acidity  is  com- 
monly tested  by  health  boards  in  cities  to  determine  the  fitness 
of  milk  for  food.  But,  as  has  been  recently  shown  by  Bergey, 
the  acid  test  will  not  apply  to  pasteurized  milk.  There  may  be 
hundreds  of  millions  of  germs  in  pasteurized  milk  without  marked 
acidity.  This  happens  because  the  germs  are  not  of  the  acid 
forming  type  but  belong  chiefly  to  the  hay  bacillus  group  (B.  sub- 
tilis). 

These  are  not  usually  rated  as  disease  germs,  but  they  make 
the  milk  less  digestible  and  nutritious  and  may  produce  substances 
in  the  milk  which  cause  severe  vomiting  and  diarrhoea  in  infants. 

By  far  the  easiest  and  most  convenient  method  of  testing  milk 
or  cream  for  acidity,  for  those  not  versed  in  chemistry,  is  by  means 
of  (Farrington's)  alkaline  tablets,  which  may  be  had  of  any  whole- 
sale dairy  supply  company.  Milk  which  contains  more  than  0.2% 
of  acid  (lactic  acid)  is  not  considered  sweet,  and  the  acidity  of 
sweet  cream  varies  from  0.15  to  0.2%.  The  Farrington  tablet 
contains  an  alkali  and  phenolphthalein.  Two  tablets  are  dissolved 
in  1  ounce  of  water  and  this  is  added  to  an  ounce  of  milk.  If 
the  mixture  remains  pink,  then  the  milk  contains  less  than  0.2%^ 


MILK  INSPECTION  191 

of  acid,  but  if  the  pink  coloration  fades  and  disappears  it  shows 
that  the  mixture  contains  more  than  this  amount  of  acid  and  is 
unfit  for  retailing,  for  pasteurizing,  or  for  cheese  or  butter  making. 
A  more  exact  method  of  using  the  tablets  for  testing  the  acidity  of 
cream  may  be  done.  This  is  very  useful  for  the  butter  maker  in 
informing  him  of  the  progress  of  the  ripening  of  cream,  and  also  in 
showing  whether  or  no  two  lots  or  cream  may  be  mixed  safely, 
and  again  it  may  be  used  to  test  the  acidity  of  whey.  When  cream 
contains  0.5  to  0.6%  acidity,  it  is  as  sour  as  it  should  be  for  butter 
making.  Full  directions  for  use  of  the  Farrington  alkaline  tablets 
are  supplied  with  the  tablets. 

A  test  by  which  the  percentage  of  acidity  of  milk  may  be  more 
accurately  determined  than  is  necessary  by  the  dairyman,  is  that 
in  which  the  alkali  is  lime  water. 

To  make  lime  water,  used  in  testing  the  acidity  of  milk,  we 
may  get  from  a  grocery  store  an  ounce  or  so  of  lime;  add  a  pint 
of  water,  and  stir  thoroughly.  Allow  the  undissolved  lime  to 
settle,  and  pour  off  the  clean  lime  water,  which  will  contain  any 
potassium  or  sodium  that  may  have  been  present  in  the  lime.  Do 
this  several  times.  Now  pour  on  a  quantity  of  distilled  water 
depending  on  the  sized  bottle  the  lime  water  is  kept  in,  and  cork; 
when  the  lime  has  settled  so  the  water  is  clear,  it  is  ready  to  be 
used  and  may  be  removed  as  wanted  with  a  pipette,  as  will  be 
described  presently.  Always  have  some  undissolved  lime  at  the 
bottom  of  the  jar,  as  by  this  means  the  lime  water  is  readily  kept 
saturated.  As  fast  as  the  lime  water  is  used,  add  distilled  water  to 
take  its  place.  It  is  well  to  use  a  fresh  lump  of  lime  every  two 
or  three  months,  as  in  time  the  sediment  may  consist  of  carbonate 
of  lime,  owing  to  absorption  of  carbonic  acid  from  the  air. 

To  test  the  acidity  of  milk  *  with  lime  water :  ( 1 )  First  mix 
the  milk  thoroughly,  and  (2)  with  a  graduated  1  c.  c.  pipette 
(such  as  is  shown  in  Fig  41)  place  1  c.  c.  of  the  milk  in  a  small 

*  This  test  is  taken  from  Chapin's  Theory  and  Practice  of  Infant  Feeding. 


1 92  CLEAN  MILK 

evaporating  dish  or  test-tube.  (3)  To  this  add  one  drop  of  an 
alcoholic  solution  of  phenolphthalein  (1  gm.  to  30  c.  c.  alcohol). 
(4)  With  another  1  c.  c.  pipette  add  drop  by  drop  clear  lime-water, 
and  shake  the  tube  to  mix  thoroughly,  until  the  milk  is  colored  a 
faint  pink.     Now  note  how  many  c.  c.  of  lime-water  were  used. 

1  c.c.  milk  and  phenolphthalein  colored  by  0.1  c.c.  lime-water  .045  p.  c.  acid- 
1    "            "                     "  "  .2     "  "  .09 

I    "  "  "  "  .3    "  "  -135 

1    "  "  "  "  .4    "  "  .180 

I     "  «  «  «  .5      "  "  .225 

1  "  "  "  "  .6  "  "  .270 

I  •/  -3o 

1  "  "  "  "  .8  "  "  .360 

1  "  "  "  .9  "  "  -405 

I  "  "  "  1.0  "  "  .450 

1  "  "  "  "  1.1  "  "  .495 

1  "  "  "  "  1.2  "  "  .540 

1  "  "  "  "  1.3  "  "  -585 

I  "  "  "  "  1.4  "  "  .630 

I  "  «  "  "  1.5  "  "  .675 

A  simple  rule  is :  Multiply  0.0045,  the  weight  in  grams  of 
lactic  acid  neutralized  by  1  c.  c.  lime-water,  by  the  number  of  cubic 
centimeters  of  lime-water  used,  and  divide  by  100,  which  gives  the 
percentage  of  acidity. 

Cream  Thickeners. — Viscogen,  a  solution  of  sugar,  lime  and 
water,  is  commonly  used  to  thicken  cream.  This  adulteration  can 
only  be  determined  by  a  chemist,  making  an  exact  analysis  for 
sugar  and  estimating  the  percentage  of  lime.  Gelatine  is  sometimes 
employed  as  a  thickening  agent.  This  can  be  detected  by  adding, 
to  about  10  or  15  cubic  centimeters  of  milk,  twice  the  volume  of 
water  and  10  cubic  centimeters  of  acid  mercuric  nitrate  solution 
(10%).  Shake  the  mixture  vigorously  and  allow  it  to  stand 
a  few  minutes  and  filter.  If  much  gelatine  is  present  it  is  im- 
possible to  filter  a  clear  fluid.  To  verify  a  suspicion  of  gelatine, 
add  to  a  small  amount  of  the  filtered  fluid  an  equal  volume  of  a 
saturated  aqueous  solution  of  picric  acid.  If  any  gelatine  is  present,. 
a  yellow  cloudiness  will  appear  in  the  fluid. 


MILK  INSPECTION 


193 


Milk  which  has  been  either  watered  or  skimmed,  or  both  wat- 
ered and  skimmed,  is  considered  according  to  law  to  be  adulterated 
and  is  the  commonest  form  of  adulteration.  To  determine  whether 
milk  has  been  watered  or  skimmed  (p.  204)  three  determinations  are 
necessary  :  viz.,  the  determination  of  the  total  solids  in  milk  ;  fat ;  and 
the  specific  gravity.  For  the  determination  of  the  specific  gravity 
and  approximate  determination  of  milk  solids,  see  pp.  197-203.  The 
determination  of  the  fat  alone  is  usually  sufficient  to  estimate  the 
quality  of  milk  for  the  farmer  who  does  not  adulterate  his  milk. 

Fig-  54- 


Small  Babcock  machine,  with  other  necessary  paraphernalia. 

The  methods  for  determining  accurately  the  amount  of  fat* 
in  milk  are  based  upon  centrifugal  separation  of  milk.  The  theory 
of  these  methods  depends  upon  the  fact  that  when  milk  is  whirled 
at  a  rapid  rate — several  thousand  revolutions  per  minute — the 
heavier  portions  of  the  milk  are  thrown  outward,  leaving  the 
lighter  or  fatty  portions  nearer  the  center  of  the  whirling  body. 
The  method  of  Dr.  S.  M.  Babcock  is  the  one  in  general  use. 

The  milk  is  measured  in  a  suitable  bottle  and  an  equal  volume 
of  sulphuric  acid  is  added  which  dissolves  the  casein  or  curd  of  milk 
and  liberates  the  fat.  The  bottle  is  then  whirled  at  a  high  speed, 
allowing  the  fat  to  come  to  the  top  of  the  bottle — that  is,  as  the 

*  For  approximate  determination  of  fat  and  solids  in  milk,  see  p.  204. 


194 


CLEAN  MILK 


bottle  is  nearly  horizontal  when  whirled,  the  fat  approaches  nearest 
the  centre  of  the  whirling  body.     Hot  water  is  added  and  the  bottle 


Fig-  55 


Eight-bottle    Babcock  machine. 

whirled  again  and  the  percentage  of  fat  is  read  off  in  the  neck  of 
the  bottle. 

Fig-  56. 


Power   Babcock.  machine. 


The  Babcock  centrifugal  machines  are  obtainable  in  sizes  rang- 
ing from  those  holding  two  bottles  (Fig.  54)  to  those  holding  24. 
(Figs.  55  and  56),  and  the  smaller  are  run  by  hand  while  the  larger 


MILK  INSPECTION  195 

are  often  run  by  power  (see  Fig.  56).  The  smaller  sizes  may  be 
clamped  or  screwed  to  a  table,  require  but  little  space  and  are  easy 
to  operate.  The  Babcock  bottle  for  milk-testing  (Frontispiece)' 
liolds  about  40  cubic  centimeters,  the  neck  is  graduated  from  o  to  10 
with  sub-divisions  of  0.2  per  cent. — 2  cubic  centimeters  being  the 
exact  volume  of  the  space  between  o  and  10 — or  10%  of  20  cubic 
centimeters,  which  volume  of  milk  would  be  used  had  milk  and 
melted  fat  the  same  specific  gravity  as  water.  It  happens,  however, 
that  2  cubic  centimeters  of  melted  fat  weighs  1.8  grams,  so  in 
working  with  the  test,  I7.6,cubic  centimeters  of  milk  (the  average 
volume  of  18  grams  of  milk)  are  used.  It  is  apparent  then  that 
the  subdivisions  on  the  stem  of  the  bottle  read  per  cent,  direct.  To 
illustrate :  Suppose  a  given  sample  reads  5  on  the  neck,  the  volume 
occupied  by  this  fat  would  be  just  one  cubic  centimeter  and  that 
would  weigh  0.9  grams,  and  0.9  grams  equal  5%  of  18  grams, 
or  the  per  cent,  of  fat  by  weight  in  the  milk. 

To  make  the  test :  The  milk  should  be  well  mixed,  and  both 
it  and  the  acid  should  be  at  a  temperature  between  6o°  and  700  F. 
The  pipette,  graduated  to  17.6  cubic  centimeters,  should  be  filled 
precisely  to  this  point,  by  sucking  up  the  milk  into  it.  The  milk 
bottle  is  to  be  held  in  a  slanting  position  and  the  point  of  the  pipette 
just  introduced  into  the  neck  of  the  bottle  (see  Fig.  58). 
By  gradually  raising  the  finger  from  the  end  of  the  pipette,  the 
milk  is  permitted  to  flow  into  the  bottle,  the  last  drop  being  expelled 
by  gently  blowing  through  the  pipette.  To  the  milk  in  the  test 
bottle,  17.6  cubic  centimeters  of  commercial  sulphuric  acid  (specific 
gravity  1.82)  are  added  in  the  same  manner  with  the  pipette,  and, 
by  gently  rotating  the  bottle,. the  acid  and  milk  are  mixed. 

The  acid  and  milk  become  very  hot  and  care  must  be  taken  to 
mix  gradually,  and  to  allow  no  lumps  to  collect  in  the  neck.  It  is 
well  to  then  let  the  bottles  stand  for  a  few  minutes,  and  mix  again 
by  rotating  the  bottles. 

The  bottles  are  now  placed  in  the  machine,  (it  is  wise  to  have 


196 


CLEAN  MILK 


duplicates  of  each  sample  of  milk)  and  the  machine  is  rotated  at 
full  speed  for  five  minutes.  Then  the  machine  is  stopped  and  boil- 
ing soft  water  is  added  to  the  contents  of  each  bottle,  by  means  of 
the  pipette  or  otherwise,  till  the  contents  of  the  bottle  rise  to  the 

Fig-  57- 


Fig-  58. 


/ 


m 


\ 


Pipette  for  making   the      Shows  method  of  introducing  milk  into  Babcock 
Babcock  test.  bottle  with  pipette  in  making  the   fat   test. 


lower  end  of  the  neck  of  the  bottle.  The  machine  is  whirled  at  full 
speed  again  for  two  minutes.  More  boiling  water  is  then  added 
to  the  contents  of  each  bottle  by  pipette  until  the  fat  rises  in  the 
neck  to  the  8  or  9  mark.     The  machine  is  once  more  turned  one 


MILK  INSPECTION  19^ 

■minute  and  the  percentage  of  fat  is  read  off  in  the  neck  of  the  bottle 
"by  measuring  with  calipers  from  the  lower  to  the  upper  border  of 
the  fat  in  the  neck.  The  reading  must  be  done  before  the  contents 
or  the  bottle  cool  off.  The  addition  of  the  hot  water  may  be 
accomplished  without  removing  the  bottles  from  the  machine  (see 
Frontispiece). 

Estimation  of  Solids  in  Milk  by  Quevenne's  Lactometer 

Since  most  cities  require  that  market  milk  shall  contain  a 
standard  percentage  of  milk  solids,  it  is  of  advantage  that  the 
farmer  be  able  to  determine  this  matter  for  himself. 

Quevenne's  lactometer  (Fig.  59)  is  an  instrument  by  which 
the  solids  can  be  roughly  estimated.  It  consists  of  a  glass  bulb 
^weighted  with  mercury  and  terminating  in  a  stem  like  a  thermom- 

Fig-  59- 


asakiJiJ^^asi^  SS3u 


Quevenne's  Lactodensimeter  or  Lactometer. 

eter,  and  marked  by  lines  on  the  stem  from  15  to  40.  It  should 
also  carry  a  thermometer. 

The  principle  upon  which  the  lactometer  is  based  depends  upon 
the  fact  that,  when  it  is  placed  in  milk,  in  floating  it  displaces  a 
"bulk  of  milk  equal  in  weight  to  the  weight  of  the  lactometer.  The 
milk  must  be  thoroughly  mixed — but  free  from  bubbles  of  air — • 
-and  the  reading  is  taken  at  the  actual  level  of  the  milk ;  not  at  the 
point  of  the  stem  to  which  it  is  drawn  by  capillary  attraction. 

The  lactometer  is  then  used  to  determine  the  weight  of  milk 
(or  in  other  words,  the  specific  gravity)  as  compared  with  the 
weight  of  an  equal  bulk  of  water  when  both  are  at  the  same 
temperature. 

If  1,000  is  taken  as  the  weight  of  a  certain  quantity  of  water, 
the  weight  of  the  same  quantity  of  milk,  at  the  same  temperature, 


198  CLEAN  MILK 

is  about  1,030  to  1,034.  This  is  shown  in  practice  by  floating  the 
lactometer  in  milk,  placed  in  a  cylindrical  glass  tube,  when  it  will 
sink  in  the  milk  to  a  mark  on  the  stem  corresponding  to  the  specific 
gravity  of  the  milk.  The  greater  weight  of  milk  (as  compared 
with  water),  or  its  specific  gravity,  is  due  to  the  solids-not-fat  it 
contains,  i.  e.,  the  casein,  albumin  and  milk  sugar.  While  the  lacto- 
meter may  be  used  to  determine  the  solids  in  unaltered  milk  as  it 
comes  from  the  cow,  it  will  not  determine  the  solids  in  milk  which 
has  been  watered  and  skimmed.  Milk  fat  weighs  less  than  water,, 
and,  of  course,  less  than  milk.  Removing  cream  raises  the  specific 
gravity  of  milk.  Then  if  water  were  added  the  specific  gravity 
might  be  lowered  again  to  the  normal  for  untampered  and  un- 
adulterated milk. 

To  estimate  the  solids  in  milk  by  the  lactometer,  the  tempera- 
ture of  the  milk  should  theoretically  be  6o°  F.  But  the  milk  .may 
be  at  any  temperature  between  500  and  70  °  F.  providing  a  correc- 
tion is  made  for  the  temperature  of  milk  above  or  below  6o°  F. 
Thus,  if  the  milk  is  above  6o°  F.,  one  must  add  to  the  lactometer 
reading  0.1  for  each  degree  of  temperature  above  this  point;  if  the 
temperature  of  the  milk  is  below  6o°  F.,  one  should  subtract  0.1 
from  the  lactometer  reading  for  each  degree  of  temperature  below 
this  point.  For  example,  if  a  sample  of  milk  at  a  temperature  of 
65  °  F.  shows  a  lactometer  reading  of  29,  then  one  should  add  to  this, 
reading: — 5  X  0.1  ==  0.5,  which  gives  the  corrected  reading  as 
29.5.  If,  on  the  other  hand,  the  lactometer  should  float  in  milk  to  a 
mark  on  its  stem  indicating  29,  and  the  temperature  of  the  milk 
was  550  F.,  then  one  should  subtract  0.1  for  each  degree  of  tem- 
perature below  6o°  F.  from  this  lactometer  reading,  which  gives 
us  28.5  as  the  corrected  reading. 

Now,  to  estimate  the  solids  in  milk  we  must  have  previously 
determined  the  percentage  of  fat  in  the  milk  by  means  of  Feser's 
lactoscope  or  the  Babcock  machine.  To  find  the  total  solids  in 
milk  we  divide  the  lactometer  reading  by  4,  and,  to  the  result,  add 


MILK  INSPECTION  199 

the  per  cent,  of  fat  multiplied  by  1.2.  For  example,  we  have  a 
milk  containing  4  per  cent,  of  fat  and  a  lactometer  reading  of  32, 
to  find  the  total  solids  : 

32-    4  =  8. 

4  per  cent.  X  i-2  =  4-8 

12.8  per  cent,  of  total  solids. 

To  find  the  solids-not-fat,  divide  the  lactometer  reading  by 
4,  and,  to  the  result,  add  the  per  cent,  of  fat  multiplied  by  0.2. 
Thus,  in  the  same  milk  as  in  the  last  example : — 

32-**     4=8. 
4  per  cent.  X  0.2  =  0.8. 

8.8  per  cent,  of  solids-not-fat. 

The  percentage  of  casein  and  albumin  increases — though  not 
in  a  proportionate  degree — with  the  increase  of  fat.  as  shown  in  the 
following  table  from  Woll's  Handbook,  summarizing  the  analyses 
of  2,400  samples  of  milk  : 


Fat 

Casein  and 

Total 

Fat 

Casein  and 

Total 

per  cent. 

albumin 

solids 

per  cent. 

albumin 

solids 

3-07 

2.92 

II.OO 

4.68 

3-57 

14.OO 

3-29 

3-° 

1 1 .  50 

4.92 

3-79 

14.50 

3-50 

3-°7 

12.00 

5-38 

4.00 

15.00 

3-75 

3*9 

I2.50 

5-69 

4.15 

r5-5° 

3-99 

3-3° 

I3.OO 

6.co 

4-30 

16.00 

4-34 

3-44 

I3-S0 

Van  Slyke  gives  the  following  formula  for  computing  the 
casein-content  from  the  known  fat-content  in  milks  containing  from 
3  to  4.5  per  cent,  of  fat :  Subtract  3  from  the  per  cent,  of  fat  in 
milk,  multiply  the  result  by  0.4,  and  add  the  result  to  2.1.  Hart 
has  shown  that  the  proportion  of  fat  to  casein  is  not  at  all  constant, 
particularly  in  the  milk  of  cows  containing  a  large  amount  of  fat. 
In  order  to  determine  more  accurately  the  percentage  of  casein  in 
milk  the  simple  test  recently  given  to  the  world  by  Prof.  E.  B.  Hart 
is  of  great  value. 

The  Hart  casein  test  depends  upon  the  following  principles: 
1.  Construction  of  tube  and  scale  whereby  percentages  of  casein 
in  the  milk  are  read  directly.    2.   Establishment  of  a  proper  volume 


200  CLEAN  MILK 

of  milk  to  be  used  that  will  conform  to  the  tube  and  scale  adopted, 
allowing  percentage  of  casein  to  be  read  directly.  3.  The  precip- 
itation of  the  casein  by  dilute  acetic  acid.  4.  The  agitation  of  the 
precipitate  with  chloroform  to  remove  the  fat.  5.  The  application 
of  a  definite  centrifugal  force  in  order  to  mass  the  casein  into  a 
pellet.     6.   Reading  the  per  cent,  of  casein. 

Special  tubes  ( Fig.  60)  made  by  E.  H.  Sargent  &  Co.,  Chi- 
cago, are  used.  The  tubes  are  5^2  inches  long  and  graduated  so 
that  each  division  on  the  scale  =  0.2  per  cent,  of  casein  when  5  c.  c. 
of  milk  are  used  in  the  test.  A  centrifuge  is  used  with  a  revolving 
wheel  15  inches  in  diameter  and  giving  2,000  revolutions  per 
minute.  A  20th  Century  Babcock  fat  tester,  made  by  the  Creamery- 
Package  Co.,  Chicago,  may  be  employed.  It  is  necessary  that  the 
diameter  of  the  machine  and  the  number  of  revolutions  performed 
shall  be  exactly  as  directed.  The  pockets  for-  the  tubes  are  made 
especially  for  the  casein  tube  and  the  bottom  of  the  pocket  is 
cushioned  from  the  graduated  part  of  the  tube  by  inserting  the 
ends  of  the  graduated  tubes  into  holes  bored  out  for  them  in  corks 
(see  Fig  60).  20  c.  c.  of  glacial  acetic  acid  in  0.25  per  cent, 
solution  is  used  for  each  tube.  The  test:  Place  tubes  in  a  rack, 
graduated-ends  down.  Drop  2  c.  c.  of  C.P.  chloroform  into  each 
tube;  then  on  top  of  the  chloroform,  drop  20  c.  c.  of  the  acetic  acid 
solution  at  approximately  700  F.  Then  add  5  c.  c.  of  milk  by 
pipette  at  temperature  ranging  from  65°-75°  F.  Shake  mixture 
with  thumb  over  aperture  of  tube  for  15  to  20  seconds  by  the 
watch.  Place  tubes  in  the  centrifuge  and  rotate.  When  machine  is 
revolving  2,000  revolutions  per  minute  keep  this  speed  for  yl/>  to  8 
minutes,  and  remove  the  tubes  to  a  rack  with  graduated  ends  down. 

To  secure  correct  number  of  revolutions,  buy  a  metronome  at  a 
music  store.  Then  count  how  many  revolutions  of  the  wheel  occur 
for  each  turn  of  the  crank.  Thus  1  turn  of  crank  =  36  revolutions, 
then  55  turns  per  minute  =  2,000  revolutions  per  minute.  The 
metronome  is  set  to  audibly  beating  this  time,  i.  c,  55  beats  per 


MILK  INSPECTION 


20I 


minute  so  that  one  can  follow  it  and  turn  the  crank  once  for  each 
beat.  After  tubes  have  rested  in  the  rack  10  minutes  the  readings 
may  be  made.  At  the  lower  end  the  chloroform,  then  the  white  mass 
of  coagulated  casein,  and  above  the  clear  solution  of  other  solids  arc 
seen  (Fig.  60).  To  read:  Hold  the  tube  perpendicularly  at  level 
of  the  eyes  and  note  the  divisions  marking  the  higher  and  lower 
levels  of  the  casein.  To  find  the  percentage  count  the  divisions 
between  these  levels,  or  subtract  the  lower  from  the  higher  level. 


Fig.  60. 


Acetic  acid. 


Casein. 


Chloroform . 


Tubes  for  Hart's  Casein  Test. 

If  a  preservative  is  used  in  the  milk,  only  potassium  dichromate  is 
suitable — 1  tablet  to  each  10  ounces  of  milk,  and  the  sample  should 
not  be  over  3  or  4  days  old. 

The  New  York  Board  of  Health  lactometer  has  a  scale  divided 
into  120  equal  parts. 

One  hundred  on  this  scale  corresponds  with  a  specific  gravity 
of  1.029,  which  is  falsely  supposed  to  represent  the  minimum 
specific  gravity  of  pure  milk;  while  o  on  the  scale  equals  1,000,  or 
the  specific  gravity  of  water.     The  whole  scale  is  founded  on  the 


202 


CLEAN  MILK 


false  premise  that  pure  milk  has  a  precise,  uniform  specific  gravity 
and  that  it  is  possible — as  it  were — to  measure  nature  with  a  yard 
stick.  Thus  the  readings  under  ioo  are  supposed  to  indicate  the 
amount  of  water  added  to  milk.  If,  for  instance,  the  reading  were 
95,  it  would  mean  that  the  milk  was  95  per  cent,  pure  and  that  it 
was  adulterated  with  5  per  cent,  of  water. 

Since  pure  milk  varies  considerably  in  specific  gravity  within 
normal  limits  the  fallacy  of  this  scale  is  apparent. 

It  would  not  receive  so  much  attention  here  were  it  not  in 
common  use  in  many  of  the  Eastern  states.  To  convert  the  read- 
ings of  the  New  York  Board  of  Health  lactometer  into  correspond- 
ing readings  of  the  Quevenne  scale  they  must  be  multiplied  by  0.29. 

QUEVENNE  LACTOMETER   DEGREES   CORRESPONDING  TO  NEW  YORK   BOARD 
OF  HEALTH   LACTOMETER   DEGREES.* 


Board  of 
Health 
Degrees. 

Quevenne 

Scale. 

Board  of 
Health 
Degrees. 

Quevenne 
Scale. 

Board  of 
Health 
Degrees. 

Quevenne 
Scale. 

Board  of 
Health 
Degrees. 

Quevenne 
Scale. 

6l 

17-7 

76 

22-0 

91 

26-4 

I06 

30-7 

62 

18-O 

77 

22-3 

92 

26-7 

I07 

3I-0 

63 

18-3 

78 

22-6 

93 

27-O 

IOS 

31-3 

64 

1S-6 

79 

22-9 

94 

27-3 

I09 

31-6 

65 

18-8 

80 

23-2 

95 

27-6 

no 

31-9 

66      • 

19-1 

81. 

23-5 

96 

27-8 

III 

32-2 

67 

19-4 

82 

23-8 

97 

28-1 

112 

32-5 

68 

19-7 

83 

24-1 

9S 

28-4 

"3 

32-8 

69 

20-0 

84 

24-4 

99 

28-7 

114 

33-i 

70 

20-3 

85 

24-6 

IOO 

29-O 

115 

33~4 

7i 

20-6 

86 

24-9 

IOI 

29-3 

Il6 

33-6 

72 

20-9 

87 

25-2 

102 

29-6 

117 

33-9 

73 

21-2 

88 

25-5 

103 

29-9 

Il8 

34-2 

74 

21-5 

89 

25-8 

104 

30-2 

II9 

34-5 

75 

21-7 

90 

26-1 

105 

30-5 

I20 

34-8 

Curd  Test. — This  is  a  good  rough  and  ready  way  to  distinguish 
clean  from  dirty  milk.  Liquid  rennet  is  added  to  warm  milk  in  a 
■milk  bottle  and  when  the  curd  has  formed  the  whey  is  poured  off. 
lAfter  the  curd  has  formed  a  compact  mass  in  the  bottom  of  the 
jar  it  should  be  cut  open.  In  dirty  milk  the  curd  is  riddled  with 
holes  like  a  sponge  owing  to  the  development  of  gas  caused  by  the 


*  Jensen's  Milk  Hygiene. 


MILK  INSPECTION  203 

growth  of  certain  bacteria.     This  condition  is  absent  in  the  curd 
from  clean  milk. 

Feser's  Lactoscope. 

This  consists  of  a  large,  hollow,  graduated  glass  cylinder,  into 
the  centre  of  the  base  of  which  is  inserted  a  smaller  white  glass  cylin- 
der marked  with  horizontal  black  lines  (Fig.  61).  The  test  with 
the  lactoscope  depends  upon  the  amount  of  dilution  of  milk  required 
in  order  that  the  lines  on  the  inner  cylinder  be  seen  when  diluted 
milk  is  placed  in  the  outer  cylinder.  The  richer  in  fat,  the  more 
opaque  is  the  specimen  and  the  greater  the  dilution  required. 

Thus  4  c.c.  of  milk  are  dropped  from  a  pipette  through  the 
aperture  in  the  top  of  the  larger  cylinder,  and  water  is  added  in 
small  amounts  and  thoroughly  mixed  with  the  milk  by  inverting 

Fig.  6r. 


'I' 'I 'I'M: 


Feser's  Lactoscope. 

the  lactoscope  with  the  finger  over  the  top.  When  the  milk  is  diluted 
sufficiently  for  the  black  lines  on  the  inner  white  cylinder  to  be 
read,  then  the  percentage  of  fat  corresponds  with  the  figures  at  the 
level  of  the  mixture  on  the  larger  graduated  cylinder  (in  an  upright 
position). 

As  has  been  stated,  the  lactometer  is  unreliable  when  used 
alone,  but,  when  employed  in  conjunction  with  the  lactoscope,  quite 
accurate  results  may  be  obtained.  While  milk  which  has  been 
skimmed  and  watered  may  show  a  normal  specific  gravity  by  the 
lactometer  reading,  so  milk  which  is  exceptionally  rich  in  fat  may 
be  only  watered  so  as  to  still  be  within  the  legal  requirements  as 
shown  by  the  lactoscope.  By  the  use  of  both  instruments,  either 
skimming  or  watering,  or  both  skimming  and  watering,  may  be 
detected — unless  the  milk  is  still  of  average  richness. 


204  CLEAN  MILK 

Harrington  (Practical  Hygiene,  p.  in)  says:  "A  norma! 
specific  gravity  with  a  low  percentage  of  fat  will  indicate  skimming 
and  watering;  low  specific  gravity  with  normal  or  low  fat,  water- 
ing; and  high  specific  gravity  and  low  fat,  skimming.  Low  specific 
gravity  with  a  high  fat  will  indicate  unusual  richness;  thus  cream 
has  a  very  low  specific  gravity,  due  to  its  preponderance  of  fat. 
As  a  test  of  the  accuracy  of  this  process  of  examination,  the  author 
caused  to  be  analyzed  under  his  supervision  1,714  specimens,  which 
appeared  by  those  tests  to  be  of  good  quality,  and  of  this  number 
but  eight  were  found  to  have  deviated  materially  from  the  statute 
requirements  of  13%  of  total  solids." 

In  case  inspection  by  lactoscope  and  lactometer  showed  a 
specimen  of  milk  below  the  legal  requirements,  this  result  should 
be  corroborated  by  the  exact  methods  of  the  laboratory  before  it 
would  be  wise  to  institute  legal  proceedings. 

If  examination  of  milk  with  both  lactometer  and  lactoscope 
shows  that  the  milk  tests  within  normal  limits  by  both  instruments, 
then  the  milk  cannot  be  much  skimmed  and  watered,  as  it  is  of 
normal  richness.  Some  considerable  experience  is  needed  in  the 
reading  of  the  lactoscope.  As  a  matter  of  fact,  in  this  city  (Seattle) 
and  many  others  the  inspector  of  milk  only  collects  samples  and 
takes  temperatures  of  milk,  the  testing  being  done  more  accurately 
in  the  laboratory. 

Selected  Forms  Used  in  the  Milk  Inspection  Service  of * 

APPLICATION  FOR  PERMIT  TO  SEND  OR  BRING  MILK  INTO 

To  the  Health  Officer,  

Sir:     In  compliance  with  'An  act  to  regulate  the  sale  of  milk  in  

and   for  other  purposes,"   I  hereby  make  application   for  a  permit  to   send  or 
bring  milk   into   said    from   the   premises    described   below,    located 


/-Whole  milk 

Number  of  shipments  per  day Total  number  of  gallons <  Skim  milk 

l  Cream. 


Forms  are  those  used  in  the  District  of  Columbia. 


MILK  INSPECTION  205- 

Shipped  in-Wagon Boat B.  and  O.  R.  R B.  and  P. 

R.  R 

Time  of  delivery Place  of  delivery 

Consigned  to 

Description  of  Premises. 


Brick Frame Stories  high 

Condition 

Is  any  part  of  it  used  for  any  other  than  dairy  purposes? 

If  so,  specify,  in  the  space  for  remarks,  what  parts  of  it  are  so  used,  and  the 

purposes  for  which  used. 
Room  for  Cattle. 

Size Long Wide High 

Floor,  kind 

Condition 

Is  it  properly  sloped  and  guttered?.. 

What  disposition  is  made  of  the  drainage? , 

Ventilation  and  lighting.     How  accomplished  ? .J 

Windows.     How  many? 

Location 

Size 

Are  windows  glazed? 

Ventilators.     How  many  ? .j 

Kind 

Location 

Size 

Doors.    How'  many  ? 

Location 

Stalls.    Where  located? 

How  many? 

Size    of    each? wide long • 

wide long 

Are  animals  of  any  kind  other  than  cattle  kept  in  this  room ?.....„ 

If  so,  specify  how  many,  and  what  kind 

Feeding  troughs  or  boxes.     How  many  ? 

Kind 

Location 

Condition 

Water  troughs.    How  many? , 

Kind 

Location 

Condition ,  Ja  . 

If  water  troughs  are  not  used,  how  are  cattle  watered? , 


Source  of  zvatcr  supply. 

If  from  well,  state  location 

Approximate  depth feet,  and  construction 

Location  of  well  with  reference  to  place  where  dung  is  deposited.     State- 

distance  and  slope  of  ground 

Has  water  any  perceptible  odor,  color,  or  taste 

If  so,  describe 


206  CLEAN  MILK 

Receptacles  for  dung  and  other  refuse.    How  many? 

Kind 

Location 

Condition 

Receptacles  for  milk.     How  many? ,> 

Kind 

Condition 

What  provision  is  made  for  cleaning? 

Is  milk  cooled  immediately  after  milking? 

If  so,  how? 

BARNYARD. 

Size long wide 

Is  it  properly  graded? and  drained? 

Is  it  paved? 

What  disposition  is  made  of  the  drainage? 

What  is  its  condition  as  to  cleanliness  at  time  of  inspection?. 


PASTURE. 

Size  of 

Condition  of 

Is  it  supplied  with  drinking  water  for  the  cattle? m 

If  so,  from  what  source? 

CATTLE. 

How  many  milch  cows  are  usually  kept? 

How  many  other  cattle,  if  any,  are  kept  in  the  same  stable? 

Kind  of  milch  cows  used 

Condition  of  cows  at  time  of  inspection.     General  condition. ...«» 

Cleanliness,  etc 

Character  of  feed , 

PRIVY   ACCOMMODATIONS. 

How  is  human  excreta  from  the  premises  disposed  of? »» 

Location  of  privy,  if  any?....... 

Construction  of  privy - 

Signature  of  applicant , 

Post-office  address 

To  the  Health  Officer, 

Sir  :     I  have  carefully  examined  the  cattle  upon  the  premises  above  referred 
to,  and  their  condition  is  as  follows: 

Signature 

Address „ 


Personally  appeared  before  me  this day  of ,   190..,  the  subscriber, 

who  being  duly  sworn  deposes  and  says  that  he  is  a  veterinary  surgeon,  practic- 
ing in  accordance  with  the  laws  of  the  State  in  which  he  resides,  and  that  he 
has  personally  examined  the  cattle  referred  to  in  the  above  statement  and  knows 
them  to  be  the  same  as  are  referred  to  in  the  application  to  which  the  certificate 
is  appended,  and  that  their  condition  is  correctly  described  without  evasion  or 
concealment. 

Signature 

Address m 


MILK  INSPECTION  207 

Health  Department,  

No ., 

DAIRY   PERMIT. 

Permission    is    hereby    granted to   maintain    a    dairy    at subject 

to  regulations  governing  dairies  within  

,  M.  D., 

Health  Officer. 

190.. 

Issued  in  accordance  with  an  "Act  to  regulate  the  sale  of  milk  in  ^ 

and  for  other  purposes,"  approved  

This    permit    is    not    transferable,    and    applies    only    to    the    premises   specified 
hereon.     If  location  is  changed,  new  permit  is  required. 


Health  Department,  « 

No 

DAIRY   FARM    PERMIT. 

Permission    is    hereby    granted to    maintain    a    dairy    farm    at 

subject  to  regulations  governing  dairy  farms  within  

,  M.  D., 

Health  Officer. 

I90-. 

Issued  in  accordance  with  an  "Act  to  regulate  the  sale  of  milk  within 

and  for  other  purposes,"  approved 

This  permit  is  not  transferable. 


Health  Department,  m 

No 

MILK   IMPORTER'S   PERMIT. 

Permission   is   hereby   granted    to  bring   or   send   milk   into    ...»...., 

from  the  dairy  farm  located  at  and  described  in  application  No 

subject  to  the  following  conditions: 

That  none  but  pure  and  unadulterated  milk  shall  be,  with  knowledge  of  its 
impurity,  brought  into  said   

That  in  the  management  of  the  dairy  farm  upon  which  the  milk  is  produced, 
or  at  the  dairy  at  which  the  milk  is  collected  and  stored  prior  to  shipment, 
the    applicant    shall    be    governed    by    the    regulations    of    the  health    office    of 

approved  by  the   Commissioners   of  said    issued  for  dairies  and 

dairy  farms  in  said   when  said  regulations  do  not  conflict  with  the  law 

of  the  State  in  which  said  dairy  or  dairy  farm  is  located. 

That  said  dairy  or  dairy  farm   may  be  inspected  at  any  time  without  notice 

by  the  health  officer  of  ,  or  his  duly  appointed  representative. 

,  M.  D., 

Health  Officer. 
100. . 

Issued   in  accordance   with   an  "Act   to   regulate  the  sale  of  milk  in    ., 

and  for  other  purposes,"  approved   

This  permit  is  not  transferable.  M 


■2o8  CLEAN  MILK 

Notice  of  violation  of  dairy  regulations. 

Any  objection  to  this  notice  should  be  filed  with  the  health  officer  before  the 
expiration  of  the  time  allowed  for  making  the  changes  specified. 

Health  Department,  

No 

DAIRY    AND    DAIRY    FARM    INSPECTION. 

,    IQO.  . 

Mr 

Sir :  Your  attention  is  called  to  the  following  violations  of  the  Regulations  for 
the  Government  of  Dairies  and  Dairy  Farms,  which  have  been  found  to  exist 
upon  your  premises: 


You  are  hereby  notified  to  correct  the  same  within days  from  the  date- 

©f  service  of  this  notice. 

By  order  of  the  health  office : 


Inspector  of  Dairies  and  Dairy  Farms. 


Cancellation   of  permit — preliminary   inspector's   notice. 

Health  Department  of  

dairy  and  dairy  farm  inspection. 

,    190.. 

M  r 

Sir:     An  inspection  of  your  dairy  farm  this  date  shows  that  you  are  violating- 

the  conditions  under  which  your  permit  No was  issued,  namely   

You  are  therefore  directed  to  show  cause  in  writing  to  the  health  officer  on. 
or  before ,  190. .,  why  your  permit  should  not  be  cancelled. 

By  order  of  health  officer: 


Inspector. 


Cancellation  of  permit — preliminary  health  officer's  letter. 

,  190.. 

Mr 

Sir:  I  have  the  honor  to  inform  you  that  the  report  of  Inspector   of 

this   department,   dated    190..,   shows   that  you   are  violating  the  condi- 
tions under  which   your  permit  No to  bring  or  send  milk  into    

was   issued;   namely    In  view  of  this   fact,  you   are  hereby   directed  to 

show  cause  on  or  before  why  your  permit  should  not  be  revoked. 

Respectfully, 

,  M.  D., 

Health  Officer. 


MILK  INSPECTION 


209 


SANITARY    INSPECTION    OF   DAIRIES. 


Owner  or  lessee  of  farm 

Town State . 


Total.  No.  of  cows No.  milking Quarts  of  milk  produced  daily 

Is  product   sold  at   wholesale   or   retail? 

If  shipped  to  dealer  give  name  and  address 

Permit  No Date  of  inspection ;  jqq 

Score. 


Score. 

Perfect. 

Allowed. 

Remarks. 

'  Cows. 
Condition   (2) 

5 
5—20 

5 
\      3—25 

1  » 

5 
5 
5—20 

5 
10—15 

5 

"Health   (8) 

Cleanliness 

Water  supply 

Stables. 

Construction 

Cleanliness 

Light 

Ventilation   (4) 

Cubic  space  per  cow  (3) 

Removal  of  manure  (2) 

Stable  yard  (1) 

Milk  house. 
Construction  (2) 

Equipment  (3) 

Cleanliness 

Care  and  cleanliness  of  utensils.  . . . 

Water  supply  (Temp °F.) 

Milkers  and  milking. 
Health  of  attendants 

Cleanliness  of  milking 

Handling  the  milk. 
Prompt  and  efficient  cooling 

(Temperature  of  milk °F.)... 

Storing  at  a  low  temperature.... 

Protection  during  transportation. . . 

5—20 

100 

• 

Total  score 



1 

Sanitary   conditions    are — Excellent Good. 

Suggestions   by   inspector 

Signed 


Fai 


Poor. 


Inspector. 


2io  CLEAN  MILK 

SANITARY   INSPECTION   OF  DAIRIES    (REVERSE   SIDE). 

DIRECTIONS  FOR  SCORING. 

cows.  Perfect 

score. 
Condition  and  healthfulness. — Deduct  2  points  if  in  poor  flesh,  and  8  points 

if   not   tuberculin-tested 10 

Cleanliness. — Clean,  5 ;  good,  4 ;   fair,  2 ;  bad,  o 5 

II 'atcr  supply. — If  clean  and  unpolluted,  5 ;  fair,  3 ;  otherwise,  0 5 

STABLES. 

Construction. — For   cement   floor    (a)*   in   good   condition   allow   2   points; 

fair,  1;  poor,  o;  wood  floor   (b)   or  other  material  in  good  condition,  1; 

fair,  J/2 ;  poor,  o;  good  tie  (c),  1;  good  manger  (d),  1;  box  stall  (c),  I..  5 
Cleanliness. — If   thoroughly    clean,    including   floor    (a),    windows    (b),   and 

ceilings  (r),  5;  good,  4;  medium,  3 ;  fair,  2;  poor,  1 ;  bad,  0 5 

Light. — Four  square  feet  of  glass  per  cow,  5 ;  1  point  off  for  each  20  per  cent 

less  than  4  square  feet  per  cow 5 

Ventilation. — Good  ventilating  system,  4;  fair,  3;  poor,  2;  bad,  o 4 

Cubic  space  per  cow. — If  500  cubic   feet  or  over  per  cow,  3 ;   less  than  500 

and  over  400,  2;  less  than  400  and  over  300,  1 ;  less  than  300,  o 3 

Removal  of  manure. — Hauled  to  field  daily,  2;  removed  at  least  30  feet  from 

stable,  1 ;  otherwise,  o 2 

Stable  yard. — In  good  condition  (a),  l/t\  well  drained  (b),  y2;  otherwise,  o.       1 

MILK    HOUSE. 

Construction. — Tight,  sound  floor,  and  not  connected  with  any  other  build- 
ing (a),  well  lighted  (b),  well  ventilated  (c),  2;  (d)  if  connected  with 
another  building  under  good  conditions,  1;  otherwise,  o;  (c)  if  no  milk 
house,  o 2 

Equipment. — Hot  water  for  cleaning  utensils  (a),  1;  cooler  (b),  1;  proper 
pails  (c)  and  strainers   (d)  used  for  no  other  purposes,  1 3 

Cleanliness. — Interior  clean,  5;  good  condition,  4;  medium,  3;  fair,  2; 
poor,  1 ;  bad,  o 5 

Care  and  cleanliness  of  utensils.— Clean  (a)  3;  kept  in  milk  house  or  suit- 
able outside  rack   (b),  2;  otherwise,  o 5 

Water  supply.— li  pure  and  clean  running  water,  5;  pure  and  clean  still 
water,  3 ;   otherwise,  0 5 

MILKING. 

Attendants.— Healthy 5 

Cleanliness  of  milking. — Clean  milking  suits,  milking  with  clean  dry  hands, 
and  attention  to  cleanliness  of  udder  and  teats  while  milking,  10;  no 
special  suits,  but  otherwise  clean  (a),  7 ;  deduct  4  points  for  uncleanly 
teats  (b)  and  udder  (r)  and  3  points  for  uncleanly  hands  (d) 10 


*  The  letters     a,  b.  c.  etc.,  should  be  entered  on  score  card  to  show  condition 
of  dairy,  and  when  so  entered  should  always  indicate  a  deficiency. 


MILK  INSPECTION 


HANDLING  THE  MILK  Perfect 

score. 
Prompt  and  efficient  cooling. — If  prompt  (a),  5;  efficient  (b),  if  50°  F.  or 
under,  5;  over  50°  and  not  over  55°.  45  over  550  and  not  over  6o°,  3;  over 

6o°,  0 ;  if  neither  prompt  nor  efficient,  o IO 

Storing  at  low  temperature. — If  500  F.  or  under,  5;  over  500  and  not  over 

55°,,  4 ;  over  550  and  not  over  6o°,  3 ;  over  6o°,  o r 

Protection  during  transportation  to  market. — If  thoroughly  protected  (iced), 
5 ;  good  protection,  4 ;  partly  protected  2 ;  otherwise,  o 5 


If  total  score  is  90  or  above  and  each  division  85%  perfect  or  over,  the  dairy  is 
Excellent    (entitled  to   registry). 

If  total  score  is  80  or  above  and  each  division  75%  perfect  or  over,  the  dairy- 
is  Good. 

If  total  score  is  70  or  above  and  each  division  65%  perfect  or  over,  the  dairy 
is  Fair. 

If  total  score  is  below  70  and  any  division  is  below  65%  perfect,  the  dairy  is 
Poor. 


[United   States   Department   of   Agriculture,  Bureau  of  Animal  Industry,  Dairy 
Division.] 

Sanitary  inspection  of  city  milk  plants. 

Owner  or  manager Trade   name „ 

City Street  and   No State 


Number  of  wagons Gallons  sold  daily 


Milk. 


Permit  or  license  No. 


Cream 

Date  of  inspection I90 


Score. 

Perfect. 

Allowed. 

Remarks. 

Milk  room. 
Location 

10 

Construction — 

Floor   (3) 

J 

[    10 

J 
IS 
10 

1 

1 

1     I5 

J 

Walls  and  ceiling   (3).. 

Drainage  (4) 

Cleanliness 

Light  and  ventilation 

Equipment — 

Arrangement   (3) 

Construction — 

Sanitary  (2) 



Durability    (2) 

Condition   (3) 



Cleanliness  (5) 

212 


CLEAN  MILK 


Milk. 

Handling  (12) 

Storage   (8) 

Sales  room. 

Location  (2) , 

Construction   (2) 

Equipment   (2) 

Cleanliness  (4) 

Wagons. 

General  appearance  (2)  . . 
Protection  of  product  (3) 
Cleanliness   (5) 

Total 


Score. 


Perfect.     Allowed. 


y  10 


Remarks. 


Sanitary  inspection  of  city  milk  plants  (reverse  side). 
DIRECTIONS  FOR  SCORING. 

MILK  ROOM. 

Location. — If  not  connected  by  door  with  any  other  building,  and  surroundings 

are  good,  10;  when  connected  with  other  rooms,  such  as  kitchens,  stables, 

etc.,  make  deductions  according  to  conditions. 
Construction. — If  good  cement  floor,  and  tight,  smooth  walls  and  ceiling,   and 

good  drainage,  allow   10;  deduct  for  cracked  or  decayed  floors,  imperfect 

wall  and  ceiling,  etc, 
Cleanliness. — If    perfectly   clean    throughout,    allow    15;    deduct    for   bad   odors, 

unclean  floor  and  walls,  cobwebs,  unnecessary  articles  stored  in  room,  etc. 
Light  and  ventilation. — If  window   space   is   equivalent   to   15%   or  more  of  the 

floor  space,  allow  5 ;  deduct  1  point  for  every  3%  less  than  the  above  amount. 


Equipment: 

Arrangement. — Allow  3  points  for  good  arrangement;  if  some  of  the  equip- 
ment is  out  of  doors  or  so  placed  that  it  can  not  be  readily  cleaned,  make 
deductions  according  to  circumstances. 
Condition. — If   in  good  repair,  allow  4  points;   make  deductions   for  rusty,. 

worn-out,  or  damaged  apparatus. 
Construction — 

Sanitary:    If  seams  are  smooth,  and  all  parts   can  be  readily  cleaned,, 
allow  2.    Deduct  for  poor  construction,  from  sanitary  standpoint. 


MILK  INSPECTION 


213 


JLquipment : 

Durability:    If  made  strong  and  of  good  material,  allow  2.     Deduct  for 
light  construction  and  poor  material. 
Cleanliness. — If  perfectly  clean,  allow  8  points;  make  deductions  according 
to  amount  of  apparatus  improperly  cleaned. 


-Handling. — If  milk  is  promptly  cooled  to  50°  F.  or  lower,  allow  12  points;  or 
if  pasteurized  at  a  temperature  of  1490  F.  or  above  and  promptly  cooled  to> 
500  or  lower,  allow  12  points.  Deduct  1  point  for  every  20  above  500.  If: 
milk  is  pasteurized  imperfectly,  deduct  6  points.  If  milk  is  improperly- 
bottled  or  otherwise  poorly  handled,  make  deductions  accordingly. 

Storage. — If  stored  at  a  temperature  of  450  F.  or  below,  allow  8  points.  Deduct 
I  point  for  every  20  above  450. 


SALES    ROOM. 

Location. — If  exterior  surroundings  are  good  and  building  is  not  connected  with 

any  other  undesirable  conditions,  allow  2;  for  fair  conditions,  allow  1;  poor 

conditions,  o. 
■Construction. — If  constructed  of  material  that  can  be  kept  clean  and  sanitary, 

allow  2;  for  fair  construction,  allow  1 ;  poor  construction,  0. 
Equipment. — If  well  equipped  with  everything  necessary  for  the  trade,  allow  2; 

fair  equipment,  1 ;  poor  equipment,  o. 
Cleanliness. — If  perfectly  clean  allow  4  points;  if  conditions  are  good,  2;  fair,  1; 

poor,  o. 

WAGONS. 

General  appearance. — If  painted  and   in  good   repair,  allow  2  points;  for  fair 

condition,  1 ;  poor,  o. 
Protection  of  product. — If  product  is  iced,  allow  3  points;  well  protected  but  not 

iced,  1  ;  no  protection,  o. 
-Cleanliness. — If  perfectly  clean,  allow  5;  good,  3;  fair,  2;  poor,  o. 


214 


CLEAN  MILK 


Score  cards  for  dairies. 
*Health  Department  of  . . 


Dairy  of 

Location Permit   N< 


Rating. 

Total 
possible 
points. 

Points, 
allowed. 

Dairy. 
Location  and  construction 

5 

I  have  this  day  carefully  in- 

Light 

5 

spected    this    dairy   and    found 
all   laws  and   regulations  fully 

Ventilation 

5 

complied   with,    except   as   fol- 
lows,   with    respect    to    which 

Screening 

5 

exceptions    appropriate    action 

Floor 

5 

Walls 

5 

, 

Drainage 

5 

Water  Supply. 
Cold' 

5 

i. 

Hot 

IO 

Facilities  for  the  cooling  and 
storage  of  milk 

IO 

Inspector. 

Equipment 

IO 

Date ,    igo 

Cleanliness  of  dairy  and   dairy 
equipment 

15 

Cleanliness  of  general  premises 

5 

Cleanliness   of   clothing,   hands, 
etc.,   of  attendants 

IO 

Total 

IOO 

Form  used  in  District  of  Columbia. 


MILK  INSPECTION 


215 


Collection  of  samples — Inspector's  memorandum  and  label 

Health  Department  of 

No 190 

Milk  ) 
Crearr  J 
Name  of  vendor. 


Address. 


Business. .  . . 
Taken  from. 
Served  by.  . 
No.  card. 
Inspector. . . 


Pt 


Amount. 


Health  Department  of. 

Specimen  No 

Purchased   as 


Time  of  purchase. 


Inspector. 


Health  Department  of. 
report  of  analysis. 


Substances  offered  for  sale  or  sold  as 
Milk Cream Skimmed  milk. 


by. 


190.. 


Analysis. 


1 

Per 
cent. 

3 

Per 

cent. 

4 

Per 
cent. 

5 

Per 
cent. 

6 

Per 

cent. 

7 

Per 
cent 

8 

Per 

cent. 

9 

Per 

cent. 

10 

Per 

cent. 

Per 

cent. 

Fit 

Remarks. 


.Analyst. 


Form  used  in  District  of  Columbia. 


216  CLEAN  MILK 

Legal  standards:     Milk.— Not  less  than  3l/2  per  cent,  fat,  9  per  cent,  solids  not 
fat,  and  not  more  than  S~l/2  per  cent,  water. 
Cream. — Not  less  than  20  per  cent.  fat. 

Skimmed  Milk. — Not  less  than  9.3  per  cent,  solids,  includ- 
ing fats. 
Wholesome  milk  must  come  from  healthy  cows  living  under  proper  sanitary- 
conditions.  It  must  have  been  properly  cared  for  at  the  time  of  milking  and 
continually  thereafter;  especially  must  it  have  been  kept  cold.  This  report 
shows  the  chemical  composition  of  the  milk  analyzed,  but  indicates  only  in  an 
imperfect  manner  its  wholesomeness,  which  can  be  determined  only  by  con- 
sidering the  condition  of  the  cows,  dairy  farm,  and  dairy  in  connection  with 
this  analysis. 

There  is  as  yet  no  fixed  standard  for  acidity  in  milk,  but  any  sample  of  milk 
or  cream  found  to  be.  in  the  judgment  of  the  health  department,  too  acid  will  be 
regarded  as  unwholesome,  and  the  seller  prosecuted. 

For  the  production  of  pasteurized  milk  on  a  large  scale  perhaps  the 
following  is  thus  far  the  most  notable  attempt  to  embody  in  serviceable 
rules  our  scientific  knowledge  of  the  effects  of  heating  milk. 

*  The  following  rules  shall  regulate  the  pasteurizing  of  milk  and 
milk  products  offered  for  sale,  exposed  for  sale,  or  kept  with  the  in- 
tention of  selling  within  the  city  of  Chicago,  after  January  1st  A.  D. 
1909: 

Rule  1.  Milk  and  skimmed  milk.  Milk  and  skimmed  milk  shall 
not  contain  more  than  100,000  bacteria  per  cubic  centimeter  from  May 
1st  to  September  30th,  and  not  over  50,000  bacteria  per  cubic  centi- 
meter between  October  1st  and  April  30th. 

Rule  2.  Cream  and  ice  cream.  Cream  and  ice  cream  shall  not 
contain  more  than  200,000  bacteria  per  cubic  centimeter  from  May 
1st  to  September  30th,  and  not  over  100.000  bacteria  per  cubic  centi- 
meter between  October  1st  and  April  30th. 

Rule  3.  Milk,  skimmed  milk,  buttermilk,  cream  and  ice  cream. 
An  original  package  of  pasteurized  milk,  skimmed  milk,  buttermilk, 
cream  or  ice  cream,  exposed  to  the  temperature  of  the  room  for  48 
hours  and  stoppered  with  a  sterile  cotton  plug,  shall  not  show  evidences 
of  putrefaction,  after  being  so  exposed. 

Rule  4.  Skimmed  milk  and  ice  cream.  Skimmed  milk  and  ice 
cream  shall  give  a  negative  test  when  treated  in  the  following  manner : 


*  From  Hoard's  Dairyman,  Dec.  4,  1908. 


MILK  INSPECTION  217 

To  5  c.c.  of  the  pasteurized  product  add  2  drops  of  a  2  per  cent. 
solution  of  paraphenylenediamin,  and  1  drop  of  a  2  per  cent,  solution 
of  hydrogen  peroxide,  and  agitate. 

Not  more  than  a  tinge  of  blue  shall  be  obtained  by  this  test  within 
30  seconds  after  mixing. 

Rule  5.     Butter.     Butter  shall  respond  to  the  following  test : 

Twenty-five  grams  of  pasteurized  butter  placed  in  a  small  beaker 
and  heated  by  being  placed  in  water  at  60  degrees  centigrade,  the  clear 
butter  fat  then  poured  off  and  the  remaining  liquid  then  diluted  with 
an  equal  volume  of  water.  The  mixture  thus  obtained  is  now  treated 
with  2  drops  of  a  2  per  cent,  solution  of  paraphenylenediamin  and  one 
drop  of  a  solution  of  2  per  cent,  hydrogen  peroxide. 

When  thus  treated  not  more  than  a  perceptible  blue  color  shall  be 
obtained  within  30  seconds  after  mixing. 

Rule  6.  Pasteurizing  temperatures.  All  pasteurized  milk,  cream, 
skimmed  milk,  milk  products,  and  milk  and  cream  used  in  the  produc- 
tion of  milk  products  shall'be  pasteurized  in  accordance  with  the  follow- 
ing regulations : 

(a)  Continuous  pasteurization — In  all  continuous  pasteurization 
the  milk  and  cream  shall  be  heated  to  a  temperature  which  shall  be 
■determined  and  fixed  by  the  department  of  health  for  each  machine 
at  a  point  corresponding  to  the  temperature  required  to  kill  99  per  cent, 
of  the  bacteria  and  all  pathogenic  bacteria  contained  in  the  raw  pro- 
duct. For  this  determination,  ordinary  raw  milk  containing  in  the 
neighborhood  of  3,000,000  bacteria  shall  be  used  and  the  pasteurized 
product  shall  be  collected  as  it  flows  from  the  cooling  apparatus. 

All  continuous  pasteurizers  shall  be  equipped  with  a  feeding  pipe 
which  is  so  constructed  that  the  pasteurizer  cannot  be  fed  in  excess 
of  its  normal  working  capacity ;  that  is,  in  excess  of  the  working  cap- 
acity of  the  machine  at  which  99  per  cent,  of  the  bacteria  are  killed 
when  the  required  amount  of  heat  is  applied. 

All  continuous  pasteurizers  operated  outside  the  city  limits,  for 
the  production  of  pasteurized  milk  and  milk  products  to  be  sold  at  the 
city  of  Chicago,  shall  be  equipped  with  an  apparatus  regulating  auto- 


218  CLE  AX  MILK 

matically  the  supply  of  steam  and  heat,  so  as  to  correspond  with  and 
produce  the  required  temperature  of  the  outflow  of  the  pasteurized 
product.  These  automatic  thermo  regulators  should  be  accurate  and 
must  be  approved  by  the  commissioner  of  health  before  being  installed. 

A  recording  apparatus  shall  be  installed  upon  all  continuous  pas- 
teurizers operated  within  the  city  limits  so  as  to  record  during  oper- 
ation the  temperature  of  the  pasteurized  product  as  it  flows  from  the 
heater.  The  thermometer  of  this  recording  apparatus  must  be  accu- 
rate and  kept  immerged  in  the  milk  in  such  a  way  that  it  is  not  exposed 
to  escaping  steam  or  other  heat  except  the  heated  milk. 

The  records  made  by  this  recording  thermometer  must  be  accurate 
and  made  in  a  chamber  which  is  kept  under  lock  and  key  in  the  con- 
trol of  the  department  of  health. 

The  automatic  thermo  regulating  and  recording  apparatus  may  be 
combined  into  one  instrument  and  it  is  recommended  that  all  pasteur- 
izers be  equipped  with  both  appliances  or  the  combination  apparatus. 

(B)  Held  pasteurization.  Whenever  milk  is  held  during  pas- 
teurization in  such  a  manner  that  the  process  of  pasteurizing  is  not  a 
continuous  one,  namely;  a  continuous  flow  of  milk  through  the  heating 
or  heat  retaining  chamber,  the  process  shall  be  designated  as  "  Held 
Pasteurization."  Such  methods  of  pasteurization  and  pasteurization 
appliances  or  systems  installed  and  used  shall  be  examined  and  approved 
by  the  commissioner  of  health,  or  his  duly  appointed  representatives, 
when  all  of  the  following  requirements  are  fulfilled: 

i.  When  the  pasteurized  product  shows  that  over  99  per  cent,  of 
the  bacteria  and  all  pathogenic  bacteria  contained  in  the  raw  product 
have  been  destroyed. 

2.  When  the  mechanism  of  the  pasteurizer  or  pasteurizing  system 
is  such  that  the  three  important  elements,  namely  :  the  temperature,  time 
of  exposure,  and  the  quantity  of  milk  exposed  at  one  time,  can  be 
readily  kept  under  control  and  observation  by  the-  department  of  health. 

3.  When  the  following  conditions  are  complied  with: 

A  uniform,  heating  of  140  degrees  F.  maintained  for  twenty  min- 
utes; 150  degrees  F.  maintained  for  15  minutes;  155  degrees  F.  main- 


MILK  INSPECTION  219 

tained  for  5  minutes;  160  degrees  F.  maintained  for  iy2  minutes;  165 
degrees  F.  maintained  for  one  minute. 

The  time  shall  be  calculated  from  the  period  that  the  entire  quantity 
reaches  the  required  temperature. 

Rule  7.  Cooling  temperatures.  The  pasteurized  product  shall 
be  cooled  at  once  to  a  temperature  of  45  degrees  F.  or  less.  This  cool- 
ing shall  be  so  conducted  that  the  pasteurized  product  is  not  exposed 
to  the  air  or  other  contamination.  This  cooling  apparatus  shall  be  so 
constructed  that  it  can  be  readily  cleaned  and  sterilized. 


CIRCULARS. 

1st— "Certified  Milk." 

Circular  of  Information  Concerning  the  Requirements  of  the 
Milk  Commission  of  the  Medical  Society  of  the  County  of 
New  York  for  "  Certified  "  Milk. 

The  Commission  appointed  by  the  Medical  Society  of  the  County 
of  New  York  to  aid  in  improving  the  milk  supply  of'  New  York  City 
invites  the  co-operation  of  the  milk  dealers  and  farmers  in  attaining 
that  end.  The  sale  of  pure  milk  is  of  advantage  to  those  furnishing 
it,  as  well  as  to  those  who  use  it.  The  Commission  has  undertaken  to 
assist  both  consumer  and  producer  by  fixing  a  standard  of  cleanliness 
and  quality  to  which  it  can  certify,  and  by  giving  information  concern- 
ing the  measures  needful  for  obtaining  that  degree  of  purity. 

The  most  practicable  standard  for  the  estimation  of  cleanliness  in 
the  handling  and  care  of  milk  is  its  relative  freedom  from  bacteria. 
The  Commission  has  tentatively  fixed  upon  a  maxium  of  30,000  germs 
of  all  kinds  per  cubic  centimeter  of  milk,  which  must  not  be  exceeded 
in  order  to  obtain  the  indorsement  of  the  Commission.  This  standard 
must  be  attained  solely  by  measures  directed  toward  scrupulous  clean- 
liness, proper  cooling,  and  prompt  delivery.  The  milk  certified  by  the 
Commission  must  contain  not  less  than  four  per  cent,  of  butter  fat,  on 


220  CLEAN  MILK 

the  average,  and  have  all  other  characteristics  of  pure,  wholesome 
milk. 

In  order  that  dealers  who  incur  the  expense  and  take  the  precau- 
tions necessary  to  furnish  a  truly  clean  and  wholesome  milk  may  have 
some  suitable  means  of  bringing  these  facts  before  the  public,  the  Com- 
mission offers  them  the  right  to  use  caps  on  their  milk  jars  stamped 
with  the  words,  "  Certified  by  the  Commission  of  the  Medical  Society 
of  the  County  of  New  York."  The  dealers  are  given  the  right  to  use 
these  certificates  when  their  milk  is  obtained  under  the  conditions 
required  by  the  Commission  and  conforms  to  its  standards. 

The  required  conditions  are  as  follows : 

I. — The  Barnyard. 

The  barnyard  should  be  free  from  manure  and  well  drained,  so  that 
it  may  not  harbor  stagnant  water.  The  manure  which  collects  each 
day  should  not  be  piled  close  to  the  barn,  but  should  be  taken  several 
hundred  feet  away.  If  these  rules  are  observed  not  only  will  the  barn- 
yard be  free  from  objectionable  smell,  which  is  always  an  injury  to  the 
milk,  but  the  number  of  flies  in  summer  will  be  considerably  diminished. 
These  flies  in  themselves  are  an  element  of  danger,  for  they  are  fond  of 
both  filth  and  milk,  and  are  liable  to  get  into  the  milk  after  having 
soiled  their  bodies  and  legs  in  recently  visited  filth,  thus  carrying  it  into 
the  milk.  Flies  also  irritate  cows,  and  by  making  them  nervous  reduce 
the  amount  of  their  milk. 

2. — The  Stable. 

In  the  stable  the  principles  of  cleanliness  must  be  strictly  observed. 
The  room  in  which  the  cows  are  milked  should  have  no  storage  loft 
above  it ;  where  this  is  not  feasible,  the  floor  of  the  loft  should  be  tight, 
to  prevent  the  sifting  of  dust  into  the  stable  beneath.  The  stables 
should  be  well  ventilated,  lighted,  and  drained,  and  should  have  tight 
floors,  preferably  of  cement.  They  should  be  whitewashed  inside  at 
least  twice  a  year,  and  the  air  should  always  be  fresh  and  without  bad 
odor.    A  sufficient  number  of  lanterns  should  be  provided  to  enable  the 


MILK  INSPECTION  221 

necessary  work  to  be  properly  done  during  dark  hours.  There  should 
be  an  adequate  water  supply  and  the  necessary  wash-basins,  soap  and 
towels.  The  manure  should  be  removed  from  the  stalls  twice  daily, 
except  when  the  cows  are  outside  in  the  fields  the  entire  time  between 
the  morning  and  afternoon  milkings.  The  manure  gutter  must  be  kept 
in  a  sanitary  condition,  and  all  sweeping  and  cleaning  must  be  finished 
at  least  twenty  minutes  before  milking,  so  that  at  that  time  the  air  may 
be  free  from  dust.  There  should  be  an  adequate  supply  of  water,  warm, 
and  cold,  and  the  necessary  wash-basins,  soap  and  towels. 

3. — Water  Supply. 

The  whole  premises  used  for  dairy  purposes,  as  well  as  the  barn,, 
must  have  a  supply  of  water  absolutely  free  from  any  danger  of  pollu- 
tion with  animal  matter,  and  sufficiently  abundant  for  all  purposes  and 
easy  of  access. 

4. — The  Cows. 

No  cows  will  be  allowed  in  the  herd  furnishing  certified  milk 
except  those  which  have  sufficiently  passed  a  tuberculin  test.  All  must 
be  tested  at  least  once  a  year  by  a  veterinarian  approved  by  the  milk- 
commission.  Any  animal  suspected  of  being  in  bad  health  must  be 
promptly  removed  from  the  herd  and  her  milk  tested.  Do  not  allow 
the  cows  to  be  excited  by  hard  driving,  abuse,  loud  talking,  or  any 
unnecessary  disturbance. 

Cleaning. — Groom  the  entire  body  of  the  cow  daily.  Before  each 
milking  wash  the  udder  with  a  cloth  used  only  for  the  udders  and  wipe 
it  with  a  clean  dry  towel.  Never  leave  the  udder  wet  and  be  sure  that 
the  water  and  towel  used  are  clean.  The  tail  should  be  kept  clean  by 
frequent  washing.  If  the  hair  on  the  flanks,  tail  and  udder  is  clipped 
close,  and  the  brush  on  the  tail  is  cut  short,  it  will  be  much  easier  to 
keep  the  cow  clean.  The  cows  must  be  kept  standing  after  the  cleaning 
until  the  milking  is  finished.  This  may  be  done  by  a  chain  or  a  rope 
under  the  neck. 

Feed. — Do  not  allow  any  strongly-flavored  food,  like  garlic,  to  be 
eaten  by  the  cows. 


222  CLEAN  MILK 

When  ensilage  is  fed,  it  must  be  given  in  only  one  feeding  daily, 
and  that  after  the  morning  milking,  and  the  full  ration  shall  consist  of 
not  more  than  20  pounds  daily  for  the  average-sized  cow.  When  fed 
in  the  fall  small  amounts  must  be  given  and  the  increase  to  the  full 
ration  must  be  gradual. 

Cornstalks  must  not  be  fed  until  after  the  corn  has  blossomed,  and 
the  first  feedings  must  be  in  small  amounts  and  the  increase  must  be 
gradual.  If  fed  otherwise,  ensilage  and  cornstalks  are  liable  to  cause 
the  milk  to  affect  children  seriously. 

5. — The  Milkers. 

The  milker  should  be  personally  cdean.  He  should  neither  have 
nor  come  in  contact  with  any  contagious  disease  while  employed  in 
milking  or  handling  milk.  In  case  of  any  illness  in  the  person  or  family 
of  any  employee  in  the  dairy,  such  employee  must  absent  himself  from 
the  dairy  until  a  physician  certifies  that  it  is  safe  for  him  to  return. 

Before  milking,  the  hands  should  be  thoroughly  washed  in  warm 
water  with  soap  and  a  nail  brush  and  well  dried  with  a  clean  towel. 
On  no  account  should  the  hands  be  wet  during  the  milking. 

In  order  that  the  milk  commission  may  be  informed  as  to  the 
health  of  the  employees  at  the  certified  farms,  the  commission  has  had 
postal  cards  printed,  to  be  supplied  to  the  farms,  and  to  be  filled  out  and 
returned  each  week,  by  the  owner,  manager,  or  physician  of  the  farm, 
certifying  that  none  are  handling  the  milk  who  are  in  contact  with  any 
contagious  disease. 

The  milkers  should  have  light-colored,  washable  suits,  including 
caps,  and  not  less  than  2  clean  suits  weekly.  The  garments  should  be 
kept  in  a  clean  place,  protected  from  dust,  when  not  in  use. 

Iron  milking  stools  are  recommended  and  they  should  be  kept 
clean. 

Milkers  should  do  their  work  quietly  and  at  the  same  hour  morning 
and  evening.  Jerking  the  teat  increases  materially  the  bacterial  con- 
tamination of  the  milk  and  should  be  forbidden. 


MILK  INSPECTION  223 

6. — Helpers  Other  Than  Milkers. 

All  persons  engaged  in  the  stable  and  dairy  should  be  reliable  and 
intelligent.  Children  under  twelve  years  should  not  be  allowed  in  the 
stable  during  milking,  since  in  their  ignorance  they  may  do  harm,  and 
from  their  liability  to  contagious  diseases  they  are  more  apt  than  older 
persons  to  transmit  them  through  the  milk. 

7. — Small  Animals. 

Cats  and  dogs  must  be  excluded  from  the  stables  during  the  time 
of  milking. 

8.— The  Milk. 

All  milk  from  cows  sixty  days  before  and  ten  days  after  calving 
must  be  rejected.  The  first  few  streams  from  each  teat  should  be 
discarded,  in  order  to  free  the  milk  ducts  from  milk  that  has  remained 
in  them  for  some  time  and  in  which  bacteria  are  sure  to  have  multi- 
plied greatly.  If  in  any  milking  a  part  of  the  milk  is  bloody  or  stringy 
or  unnatural  in  appearance,  the  whole  quantity  of  milk  yielded  by  that 
animal  must  be  rejected.  If  any  accident  occurs  in  which  a  pail  be- 
comes dirty,  or  the  milk  in  a  pail  becomes  dirty,  do  not  try  to  remove 
the  dirt  by  straining,  but  put  aside  the  pail,  and  do  not  use  the  milk  for 
bottling,  and  use  a  clean  pail. 

Remove  the  milk  of  each  cow  from  the  stable  immediately  after  it 
is  obtained  to  a  clean  room  and  strain  through  a  sterilized  strainer  of 
cheesecloth  and  absorbent  cotton. 

The  rapid  cooling  is  a  matter  of  great  importance.  The  milk 
should  be  cooled  to  45 °  F.  within  an  hour  and  not  allowed  to  rise  above 
that  as  long  as  it  is  in  the  hands  of  producer  or  dealer.  In  order  to 
assist  in  the  rapid  cooling,  the  bottles  should  be  cold  before  the  milk  is 
put  into  them. 

Aeration  of  milk  beyond  that  obtained  in  milking  is  unnecessary. 

9. — Utensils. 

All  utensils  should  be  as  simple  in  construction  as  possible  and  so 
made  that  they  may  be  thoroughly  sterilized  before  each  using. 


224  CLEAN  MILK 

Coolers,  if  used,  should  be  sterilized  in  a  closed  sterilizer,  unless  a 
very  high  temperature  can  be  obtained  by  the  steam  sent  through  them. 

Bottling  machines  should  be  made  entirely  of  metal  with  no  rubber 
about  them,  and  should  be  sterilized  in  the  closed  sterilizer  before  each 
milking,  or  bottling. 

If  cans  are  used,  all  should  have  smoothly  soldered  joints,  with  no 
places  to  collect  the  dirt. 

Pails  should  have  openings  not  exceeding  8  inches  in  diameter,  and 
may  be  either  straight  pails,  or  the  usual  shape  with  the  top  protected 
by  a  hood. 

Bottles  should  be  of  the  kind  known  as  "  common  sense,"  and' 
capped  with  a  sterilized  paraffined  paper  disk,  and  the  caps  authorized 
by  the  commission. 

All  dairy  utensils,  including  the  bottles,  must  be  thoroughly 
cleansed  and  sterilized.  This  can  be  done  by  first  thoroughly  rinsing 
in  warm  water,  then  washing  with  a  brush  and  soap  or  other  alkaline 
cleansing  material  and  hot  water  and  thoroughly  rinsing.  After  this 
cleansing  they  should  be  sterilized  by  boiling,  or  in  a  closed  sterilizer 
with  steam,  and  then  kept  inverted  in  a  place  free  from  dust. 

10. — The  Dairy. 

The  room  or  rooms  where  the  utensils  are  washed  and  sterilized 
and  milk  bottled  should  be  at  a  distance  from  the  house,  so  as  to  lessen 
the  danger  of  transmitting  through  the  milk  any  disease  which  may 
occur  in  the  house. 

The  bottling  room,  where  the  milk  is  exposed,  should  be  so  situated 
that  the  doors  may  be  entirely  closed  during  the  boiling  and  not  opened 
to  admit  the  milk  nor  to  take  out  the  filled  bottles. 

The  empty  cases  should  not  be  allowed  to  enter  the  bottling  room 
nor  should  the  washing  of  any  utensils  be  allowed  in  the  room. 

The  workers  in  the  dairy  should  wear  white  washable  suits,  in- 
cluding cap,  when  handling  the  milk. 

Bottles  must  be  capped,  as  soon  as  possible  after  filling,  with  the 
sterilized  disks. 


MILK  INSPECTION  225 

11. — Examination  of  the  Milk  and  Dairy  Inspection. 

In  order  that  the  dealers  and  the  Commission  may  be  kept  in- 
formed of  the  character  of  the  milk,  specimens  taken  at  random  from 
the  day's  supply  must  be  sent  weekly  to  the  Research  Laboratory  of  the 
Health  Department,  where  examinations  will  be  made  by  experts  for 
the  Commission  ;  the  Health  Department  having  given  the  use  of  its 
laboratories  for  this  purpose. 

The  Commission  reserves  to  itself  the  right  to  make  inspections  of 
certified  farms  at  any  time  and  to  take  specimens  of  milk  for  examina- 
tion. It  also  reserves  the  right  to  change  its  standards  in  any  reason- 
able manner  upon  due  notice  being  given  to  the  dealers. 

After  January  I,  1902,  the  expenses  incurred  in  making  the 
regular  milk  examinations  and  inspections  will  be  borne  by  the  dealers. 
In  fixing  the  charges  each  farm  or  group  of  farms  will  be  considered  a 
unit.  The  Secretary  of  the  County  Medical  Society  will  send  the  bills 
to  the  dealers  about  the  middle  of  each  month.  Prompt  payment  is 
requested. 

The  monthly  charges,  which  are  intended  to  cover  all  expenses, 
will  be  as  follows  : 

For  each  group  of  farms  sending  daily  less  than  100  quarts  $8.oc» 

100  to  200  10.00 

200  to  500  12.00 

over  500  15.0O' 

2d.— "  Inspected  Milk." 

Circular  of  Information  Concerning  the  Requirements  of  the 
Milk  Commission  of  the  Medical  Society  of  the  County  of 
New  York  for  "  Inspected  "  Milk. 

The  Commission  appointed  by  the  Medical  Society  of  the  County 
of  New  York  to  aid  in  improving  the  milk  supply  of  New  York  City 
has  formulated  the  following  requirements,  affecting  the  farms  in- 
spected by  it  and  the  handling  of  the  milk  obtained  at  these  farms. 


226  CLEAN  MILK 

The   Commission  offers  those  dealers   complying  with   these  require- 
ments the  right  to  use  caps  on  their  milk  bottles,  stamped :   "  Inspected. 
Milk  Commission  Medical  Society,  County  of  New  York." 
The  requirements  are  as  follows : 

i-     The  Barnyard. 

(a)  It  must  contain  no  manure  in  summer  and  none  in  contact  with 

the  stable  in  winter. 

(b)  It  must  be  well  drained  and  kept  reasonably  clean. 

2.     The  Stables. 

(a)  The  ventilation  and  light  must  be  sufficient  for  the  number  of 

cows  stabled,  so  that  the  barn  shall  be  light  and  the  air 
never  close. 

(b)  The  floor  shall  be  wood  or  cement. 

(c)  The  ceiling  shall  be  tight,  if  a  loft  above  is  used. 

(d)  Basins,  hand  brushes,  clean  water,  soap  and  clean  towels  shall 

be  provided  in  the  barn  or  adjacent  dairy  room. 

(e)  The  stable  shall  be  whitewashed  in  the  fall,  and  in  the  spring 

if  necessary. 

(f)  A  sufficient  number  of  lanterns  shall  be  provided  to  allow  the 

milking  to  be  carried  on  properly. 

(g)  Clean  the  ceilings  and  sidings  once  a  month. 

(h)  The  bedding  shall  be  shavings,  sawdust,   dried  leaves,  cut 

straw,  or  other  material  that  meets  the  approval  of  the 

Commission, 
(i)   The  soiled  bedding  must  be  removed  daily, 
(j)   The    manure    must    be    removed    from    the    stalls    and    open 

manure-gutter.     If  a  covered  manure-gutter  is  used,  it 

must  be  kept  in  a  sanitary  condition. 
(k)   The  application  of  land-plaster  or  lime  on  the  floor  daily  is 

recommended. 
(1)   Sweep  the  entire  floor  outside  the  stalls  daily  at  least  an  hour 

before  milking  is  begun. 


MILK  INSPECTION  22? 

Water  Supply. 

Pure  water  must  be  used  for  all  purposes.     It  must  be  ac- 
cessible and  abundant. 

The  Cows. 

(a)  Discard  milk  containing  mucus  or  blood  and  that  from  any 

diseased  cow. 

(b)  Reject  milk  from  any  animal  forty-five  days  before  and  six 

days  after  calving. 

(c)  The  food  given  must  be  suitable  both  in  amount  and  kind  and 

must  not  give  a  disagreeable  flavor  to  the  milk. 
'(d)   Keep  the  cows  clean  on  flanks,  belly,  udder  and  tail. 

(e)  Clip  long  hairs  about  udders  and  clip  the  tail  sufficiently  to> 

clear  the  ground. 

(f)  The  cows  must  be  kept  from  lying  down  between  the  cleaning- 

and  milking.    The  best  means  of  accomplishing  this  is  by 
throatlatches. 

(g)  Clean  the  udder  thoroughly  before  milking. 

The  Milkers. 

(a)  No  milker  or  assistant  shall  have  any  connection  with  the 
milk  at  any  stage  of  its  production  if  he  has  any  com- 
municable disease,  or  if  he  has  been  exposed  to  scarlet 
fever,  diphtheria,  typhoid  fever,  or  small-pox. 

'(b)  After  having  everything  prepared  for  milking,  thoroughly 
wash  the  hands  with  soap,  water,  and  brush,  so  that  they 
may  be  clean  when  milking  is  begun. 

(c)  The  hands  and  teats  must  be  kept  dry  during  milking.     If 

they  become  moistened  with  milk,  they  must  be  wiped  dry 
with  a  clean  towel. 

(d)  Suitable  clean  outer  garments,  such  as  overalls  and  jumpers, 

must  be  put  on  before  milking. 

Utensils. 

(a)  Strainers,  whether  metal,  gauze,  or  cotton,  must  be  absolutely 

clean  when  used  for  straining  milk. 

(b)  All  dairy  utensils  must  be  absolutely  clean  and  free  from  dust. 


228  CLEAN  MILK 

The  Milk. 

1.  The  milk  must  not  be  adulterated  in  any  way. 

2.  It  must  average  3.6  per  cent,  of  butterfat. 

3.  Cooling  must  begin  at  once.  The  temperature  of  the  milk-, 
must  be  reduced  to  50°  F.  within  two  hours  and  kept  below  that  tem- 
perature until  delivered  to  the  consumer. 

4.  When  delivered  to  the  consumer  the  milk  must  not  average 
over  100,000  bacteria  per  cubic  centimeter  from  May  1st  to  September 
30th,  and  not  over  60,000  bacteria  per  cubic  centimeter  from  October 
1st  to  April  30th.  If  the  Commission's  requirements  are  fulfilled,  the 
"bacteria  will  not  be  in  excess  of  the  number  permitted. 

Inspections. 

1.  The  farms  which  furnish  inspected  milk  must  always  be  open 
to  inspection  by  the  Commission. 

2.  Samples  of  milk  must  be  regularly  submitted  for  bacteriologi- 
cal examination  once  a  month. 

Working  Methods  and  Standards.* 

While  the  aims  and  general  requirements  of  the  different  com- 
missions are  similar,  there  has  been  considerable  diversity  in  respect 
to  details,  most  of  them,  however,  of  a  nonessential  character. 

The  original  plan  outlined  the  fundamental  requirements,  and  it 
remained  for  each  commission  to  develop  working  methods  and  stand- 
ards suitable  to  its  particular  locality. 

In  any  case  the  commission  agrees  to  certify  to  milk  conforming 
to  its  standards  when  produced  in  well-equipped  dairies  conducted 
in  accordance  with  prescribed  sanitary  requirements. 

In  order  that  these  facts  may  be  determined,  a  veterinary  surgeon,, 
a  bacteriologist,  and  a  chemist  are  selected  by  the  commission. 

When  a  dairyman  signifies  his  willingness  to  co-operate  in  the  pro- 
duction of  pure  milk,  the  veterinary  surgeon  visits  the  farm  and  in— 


*  From  Bull.  41.    Hygienic  Laboratory,   1908,  U.  S.  Treasury  Dep't. 


MILK  INSPECTION  229 

'.spects  the  buildings,  their  location,  and  sanitary  condition.  He  also 
observes  the  hygienic  methods  employed  in  the  production  and  hand- 
ling of  the  milk,  and  physically  examines  the  cows  in  the  herd. 

If  it  is  financially  possible  a  physician  should  visit  a  farm  supply^ 
ing  certified  milk  at  weekly  intervals.  Postal  cards  should  be  supplied 
the  farm  superintendent,  on  which  he  should  report  the  existence  of  any 
illness  (including  sore  throat)  on  the  premises.  The  physician  should 
inspect  to  determine  the  presence  of  any  illness  among  the  employees 
or  their  families  and  especially  as  to  the  existence  of  scarlatina,  diph- 
theria, typhoid  fever,  consumption  and  skin  diseases.  The  general 
hygienic  condition  of  the  employees,  premises  and  quality  of  the  water 
supply  should  be  reported.  The  precise  number  of  employees  must  be 
ascertained  and  cases  of  recent  illnesses  investigated. 

Veterinary  inspection  should  be  made  with  particular  reference  to 
tovine  infections  which  may  be  communicated  to  man  in  milk.  r. 
Such  general  infections  of  cattle  include — tuberculosis,  cowpox,  tet- 
anus, anthrax,  foot  and  mouth  disease,  black  quarter,  rabies,  trembles, 
contagious  pleuro-pneumonia  and  actinomycosis.  It  is  somewhat  doubt- 
ful whether  the  latter  can  be  conveyed  to  man  by  milk.  2.  Infections 
of  the  digestive  tract  in  which  germs  in  the  feces  are  likely  to  contam- 
inate milk.  These  include  enteritis,  dysentery  and  calf  cholera.  Milk 
from  cows  suffering  from  digestive  disturbances  is  unfit  for  use,  since 
it  may  contain  deleterious  chemical  bodies.  3.  Mastitis  of  various 
-sources,  as  that  due  to  tubercle  and  colon  bacilli,  streptococci  and 
staphylococci,  B.  necrophorous  and  actinomycosis.  4.  Local  infections 
elsewhere,  as  septic  metritis,  abscesses,  suppurating  wounds  and  nec- 
rosis. 5.  Any  acute  disease  in  which  toxins  and  perhaps  micro-organ- 
isms may  escape  in  the  milk. 

In  a  general  way  it  may  then  be  said  that  bacteriological  examina- 
tions of  certified  milk  should  be  made  weekly,  chemical  examinations 
and  veterinary  inspections  monthly,  and  medical  inspections  weekly 
or  as  circumstances  may  require. 

This  examination  also  includes  the  application  of  the  tuberculin 
test.  These  inspections  are  subsequently  made  at  frequent  intervals 
and  reports  are  made  to  the  commission,  the  following  being  a  con- 
-venient  form  in  use  at  Cleveland  and  other  places : 


230  CLEAN  MILK 

Inspector's  report.     Dairy  of  Date   

Herd:  Milking  cows  Dry  cows   Hospital  cows 

Cows  recently  calved Cows  added  since  last  report  

Not  yet  tuberculin  tested  Quarantined  

Stable:  Cleanliness Ventilation Temperature  

Dairy  building:  Cleanliness Ventilation Temperature 

Other  buildings  

Utensils 

Care  and   cleanliness   in  milking   

Food   

Health  of  employees 

Remarks    

Based  upon  the  foregoing  inspection  made  at  the  request  of  The  Milk- 
Commission  of  the  city  of  Cleveland,  I  beg  to  report  that  this  dairy  conforms 
to  the  requirements  of  said  commission  and  recommend  that  its  milk  be 
submitted  to  the  bacteriologist  and  chemist  for  their  examinations. 

(Signed) ,  Veterinarian. 

The  chemist  and  bacteriologist  each  examine  from  time  to  time 
at  the  discretion  of  the  commission,  samples  of  the  milk  taken  at 
random  or  purchased  on  the  open  market. 

The  former  determines  the  specific  gravity,  acidity,  percentage  of 
fats,  sugar,  proteids,  water  and  mineral  matter  present,  and  the  presence 
or  absence  of  preservatives  and  chemical  adulteration.  The  latter  deter- 
mines the  number,  and  so  far  as  practicable,  the  character  of  bacteria 
and  the  presence  or  absence  of  pus  cells. 

The  following  forms  are  convenient  for  rendering  the  reports  of 
these  examinations : 

No Dairy Date 

Distributer   Collected  by  

Sealing Date  of  milking 

Hour  collected Temperature  when  collected  °F. 

General  condition:  Color Odor Taste 

Separation  of  cream    Macroscopic  sediment    

Chemical  composition:  Specific  gravity Acidity Total %, 

Fat %.     Sugar %.     Proteids %. 

Salts %.    Ash %. 

Preservatives Coloring  matters Adulterants 

Remarks   

The  examination  recorded  above,  made  at  the  request  of  The  Milk  Commis- 
sion of  the  city  of  Cleveland,  shows  a  <  m\  j  reaching  the  chemical  standard, 
adopted  by  the  commission. 

(Signed) ,    Chemist. 

[The  foregoing  card  is  printed  on  pink  paper.] 


MILK  INSPECTION  231 

"No Dairy Date 

Distributer    Collected   by    

Sealing    Date  of  milking   

Hour  collected   Cultures   made   Temperature  when  examined 

°F. 

General  condition:  Color  Odor  Taste  , 

Separation  of  cream Macroscopic  sediment 

Bacteriological  examination:   Media   

Temperature   Dilution   

Bacteria  per  c.  c Average 

Pathogenic  bacteria    

Microscopic  examination,  blood,  pus,  tubercle  bacilli,  etc 

The  examination  recorded  above,  made  at  the  request  of  The  Milk  Com- 
mission of  the  city  of  Cleveland,  shows  a  <  ^earn  f  reacnnig tlie  chemical  standard 
standard  adopted  by  the  commission. 

(Signed) ,  Bacteriologist. 

[The  foregoing  card  is  printed  on  light  blue  paper.] 
It  is  generally  believed  that  the  bacteriological  examination  should 
be  repeated  once  a  week,  the  chemical  examination  once  a  month, 
and  the  veterinary  inspection  once  a  month — the  tuberculin  test  to 
"be  used  on  every  new  cow  added  to  the  herd  and  reapplied  at  least 
once  or  twice  a  year. 

Inquiry  is  also  made,  usually  by  a  member  of  the  commission, 
regarding  the  health  of  employees,  and  in  addition,  the  dairyman  is 
in  certain  instances  required  to  render  a  regular  report  regarding  the 
presence  or  absence  of  communicable  diseases  among  the  dairy  per- 
sonnel. The  following  form  is  used  at  Cleveland,  Ohio,  for  this 
purpose : 

For  the  information  of  The  Milk  Commission,  I  hereby  answer  the  follow- 
ing questions  for  the  week  ending   ,19    . 

I.  Are  any  of  the  men  handling  milk  at  your  farm  ill  with  any  communicable 
disease?    

II.  Is   there  any  communicable  disease  in  the   families   with  which  they   are 
connected? 

III.  Have  any  been  in  contact  with  any  communicable  disease  and  then  ex- 
cluded from  the  milking  place? 

IV.  Shipments  of  certified  milk  and  cream  in  past  week: 

(a)   Quarts  of  certified  milk   (b)   Pints  of  certified  cream 

(c)   Bottles  of  certified  milk (d)   Bottles  of  certified  cream 

V.  How  many  unbroken  boxes  of  caps  have  you? 

(Signed)    


232  CLEAN  MILK 

Upon  these  reports  the  commission  bases  its  action  in  respect  to 
certification  and  the  certificates  are  renewed  once  a  month. 

The  dairyman  is  thus  authorized  to  indicate  such  indorsement, 
either  by  using  on  his  bottle  a  cap  bearing  the  name  of  the  Medical 
Milk  Commission  and  the  term  "  certified  milk "  or  a  copy  of  the 
certificate. 

In  New  York  the  law  forbids  the  use  of  the  term  "  certified  "  on  the 
cap  unless  accompanied  by  the  name  of  the  society  which  certifies  it, 
and  in  some  other  places  the  certificates  bear  a  copyrighted  monogram 
to  prevent  their  fraudulent  use. 

For  examples  of  these  methods  of  designating  such  milk,  see  Fig. 

51,  p.  169. 

When  the  certificate  form  is  used  it  is  placed  between  the  cap  and 
a  parchment  covering  the  neck  of  the  bottle,  and  in  either  case  the 
date  of  milking  must  appear,  a  rubber  or  impression  stamp  being  used 
for  the  purpose. 

In  some  instances  the  bottles  are  hermetically  sealed  with  paraffin, 
which  is  protected  by  parchment,  tin  foil  or  tin  covers  bearing  the 
term  "  certified,"  the  name  of  the  dairy  and  the  name  of  the  Medical 
Milk  Commission.  The  caps  are  sometimes  sold  to  the  dairymen  by 
the  commissions  and  funds  are  thus  provided  for  defraying  the  nec- 
essary expenses,  including  inspections,  chemical  analyses,  etc.  In 
other  instances  funds  are  provided  by  the  medical  society,  the  dairy- 
man or  by  means  of  a  bottle  tax. 


CHAPTER  X 


ESSENTIALS  OF  MILK  BACTERIOLOGY 
By  H.  W.  Hill,  M.  D. 


THE  Bacteria  are  very  minute  living  things,  which  feed 
chiefly  on  the  waste  matters  of  animal  and  vegetable  life, 
and  on  dead  animal  and  vegetable  bodies.  There  are  many 
kinds  of  bacteria,  one  differing  from  another  in  size  to 
some  extent,  in  shape  to  some  extent,  but  chiefly  in  the  way  they 
live — the  kind  of  food  they  prefer,  the  kind  of  atmosphere  they 
need,  the  temperature  at  which  they  will  develop,  the  products  they 
form  from  their  food,  the  shape  and  naked-eye  appearance  of  their 
mass  growths.  Hence,  although  the  size  and  shape  of  any  given 
bacterium  helps  towards  its  recognition,  it  must  be  tested  in  many 
ways  to  determine  the  foods  it  uses,  its  effect  on  its  foods,  the  tem- 
perature and  atmosphere  best  suited  to  it,  and  other  details,  before 
any  one  who  examines  it  can  determine  its  identity.  No  bacteriol- 
ogist can  recognize  what  bacterium  he  is  dealing  with  by  merely 
looking  at  it  with  a  microscope,  except  in  a  very  few  special  cases. 
The  bacteria  have  no  sex.  New  ones  are  formed  simply  by  the 
division  of  the  old  ones  into  two  (fission).  Size,  shape  and 
-arrangement,  i.  c,  grouping  of  individuals  in  chains,  clusters,  etc., 
are  studied  under  the  term  morphology;  the  essentials  of  growth, 
reproduction,  food,  chemical  products,  etc.,  under  physiology. 

Size. — The  diameters  of  the  bacteria  in  general  range  from 
about  1/25,000  of  an  inch  (or  1/1000  of  a  millimeter,  which  is 

233 


234  CLEAN  MILK 

called  i  ix  or  mu  or  micron)  to  three  or  four  times  as  much.  The 
diameter  of  the  individuals  belonging  to  any  one  species  varies  very 
little.  The  length  of  bacteria  in  general  ranges  from  1/25,000  of 
an  inch  to  very  many  times  that  figure — perhaps  to  1/16  of  an  inch 
or  more  amongst  the  higher  bacteria,  but  these  very  long  forms  are 
twisted  and  curled,  never  extended  in  a  straight  line.  The  length 
of  the  individuals  belonging  to  any  one  species  varies  very  greatly, 
according  to  age  and  other  conditions.  Hence,  in  examining  bac- 
teria under  the  microscope,  great  differences  in  length  do  not  neces- 
sarily indicate  that  more  than  one  species  is  present;  but  if  differ- 
ences in  diameter  are  found,  the  observer  may  feel  pretty  certain 
that  he  is  dealing  with  a  mixture  of  several  kinds;  on  the  other  hand, 
it  is  quite  possible  to  have  two  different  kinds  of  the  same  diameter : 
in  such  cases  the  shape  of  the  individuals  may  assist  in  deciding 
whether  one  or  more  kinds  are  present. 

Shape. — The  bacteria  present  very  simple  symmetrical  outlines 
— so  simple  that  there  is  little  room  for  great  differences  between 
them.  The  simplest  form  is  spheroidal,  some  kinds  being  truly 
round,  others  flattened  slightly.  The  rest  of  the  bacteria  are  more 
or  less  cylindrical.  Of  these  cylindrical  forms,  some  are  short, 
others  very  long,  others  intermediate.  The  short  cylindrical  bac- 
teria are,  in  some  species,  twisted  spirally.  Some  few  bacteria 
branch. 

Structure  of  Bacteria. — The  individual  bacterium  is  composed 
of  practically  the  same  material  as  are  all  other  living  things — 
protoplasm.  Chemical  tests  cannot  distinguish  the  protoplasm  of 
the  animal  from  that  of  the  vegetable,  nor  the  protoplasm  of  either 
of  these  from  the  protoplasm  of  the  bacterium.  That  the  protoplasm 
of  the  animal  varies,  nevertheless,  from  that  of  the  vegetable,  and 
both  from  bacterial  protoplasm,  is  known,  because  each  grows  and 
acts  in  a  manner  peculiar  to  itself  in  many  details.  The  minute  par- 
ticle of  protoplasm  which  forms  a  bacterium  is  enclosed  in  a  wall, 
composed  of  a  chitin-like  material  similar  to  that  which  forms  the 


ESSENTIALS  OF  MILK  BACTERIOLOGY  -235 

carapace  of  the  lobster,  or  the  outer  wing-cases  of  beetles.  Vege- 
table protoplasm,  on  the  other  hand,  is  contained  usually  in  a  cell 
Avail  of  cellulose,  while  animal  protoplasm  has  no  wall  distinct 
in  composition  from  its  own  substance.  The  protoplasm  of  the 
bacterium,  contained  in  its  surrounding  wall,  forms  what  is  called  a 
cell,  and  since  each  such  cell,  amongst  the  bacteria,  is  complete  in 
itself  and  capable  of  independent  existence,  feeding,  growing,  multi- 
plying, excreting,  dying,  the  bacteria  are  spoken  of  as  uni-cellular 
organisms.  Some  minute  vegetable  and  animal  organisms  are  uni- 
cellular also,  but  the  larger  forms  are  composed  of  many  cells  at- 
tached to  each  other  and  interdependent  on  each  other.  This  inter- 
dependence is  due  to  the  fact  that  in  such  multicellular  organisms 
specialization  has  gone  on,  so  that  certain  cells  secrete  digestive 
juices,  other  cells  are  devoted  to  reproduction  and  so  on.  Amongst 
the  uni-cellular  organisms,  each  cell  performs  all  these  functions 
itself. 

Besides  the  cell-wall  and  its  protoplasmic  contents,  both  of 
which  all  bacteria  possess,  some  bacteria  possess  flagella,  or  fine 
liairlike  whips  only  to  be  seen  by  special  methods  of  staining,  the 
use  of  which  is  to  propel  the  bacterium  possessing  them  through 
liquid — they  are  the  swimming  organs  of  the  "  motile  "  bacteria. 
Bacteria  without  flagella  are  incapable  of  swimmiing  and  are  called 
non-motile.  Motility,  i.  e.,  true  purposive  swimming  movements, 
must  be  distinguished  from  the  Brownian  movement.  This  is  a 
vibratory,  sometimes  circular  motion  which  all  minute  particles  sus- 
pended in  liquid  are  likely  to  show,  due  to  the  delicacy  with  which 
they  are  held  balanced  in  liquids,  and  the  constant  direct  trans- 
mission to  the  liquid  of  minute  vibrations  from  outside.  Particles 
of  resin,  milk  globules,  dust  particles,  dead  bacteria,  etc..  suspended 
in  liquid  show  this  movement.  In  case  of  doubt  between  motility 
and  Brownian  movement,  the  distinction  can  be  based  on  the  trans- 
lation from  place  to  place,  resulting  from  motility,  in  contrast  to 
the  -absence  of  movement  from  place  to  place  (except  within  the 


236  CLEAN  MILK 

small  area  of  the  vibratory  motion),  seen  in  true  Brownian  move- 
ment. Brownian  movement  of  a  particle  combined  with  an  actual 
current  in  the  liquid  in  which  it  is  suspended  may  give  an  appear- 
ance of  actual  translator)-  motion  much  like  true  living  motility, 
but  can  be  distinguished  from  it  in  that  the  current  movement  is 
all  in  some  one  direction,  while  individual  bacteria  showing  motility 
move  in  various  directions. 

Certain  bacteria  at  certain  stages  (generally  when  growth  has 
occurred  rapidly  in  one  place  for  a  considerable  number  of  hours, 
resulting  in  food  exhaustion;  or,  more  often,  from  the  accumulation 
of  bacterial  excreta  in  sufficient  amount  to  obstruct  further  growth 
by  poisoning  the  living  bacteria;  or  when  drying,  if  it  occurs 
slowly)  form  spores,  which  are  bodies  developed  in  the  cell  (one 
spore  to  one  cell  usually)  containing  the  living  protoplasm  of  the  cell 
in  a  dormant  state,  and  having  a  spore  wall  of  greater  strength  and 
resistance  than  the  wall  of  the  parent  cell.  A  cell  containing  a  spore 
is  called  a  sporangium.  The  sporangium  soon  disintegrates,  setting- 
the  spore  free.  The  spore  remains  alive  but  dormant  until  it  reaches 
a  locality  where  conditions  of  food,  temperature,  etc.,  are  favorable, 
whereupon  it  germinates — i.  e.,  the  protoplasm  within  it  becomes 
active  and  begins  to  grow,  escaping  from  the  confines  of  the  spore 
wall  and  resuming  existence  in  the  identical  form  and  activities  of 
its  parent  cell.  Spores  are  particularly  important  to  the  milk  bac- 
teriologist, because  the  measures  of  sterilization,  etc.,  wholly  efficient 
in  the  case  of  the  ordinary  bacterial  cell,  may  fail  if  spores  are 
present,  since  the  latter  are  much  more  resistant  to  heat,  drying 
chemical  reagents,  etc.,  than  the  adult  bacterial  cell. 

"  Capsules  "  show  themselves  as  oval  rings  or  halos,  surround- 
ing bacterial  cells.  They  are  to  be  found  more  readily  in  some 
species  than  in  others,  although  by  no  means  constantly  in  any 
species.  It  cannot  be  doubted  that  many  appearances  interpreted 
as  indicating  capsules  are  really  artefacts  or  optical  illusions. 
Nevertheless  it  is  not  improbable  that  a  true  bacterial  substance 


ESSENTIALS  OF  MILK  BACTERIOLOGY  237 

<ioes  at  times  exist  surrounding  the  bacterial  cell  outside  of  the  cell 
Avail,  as  the  white  of  an  egg  surrounds  the  yolk.  Whether  this  is 
a  secretion  of  the  cell  or  a  mere  swelling  up  of  the  cell-wall,  or 
sometimes  one,  sometimes  the  other,  is  not  known. 

Classification.— The  bacteria  have  for  convenience  been  divided 
according  to  shape  into  families:  the  families  have  been  divided, 
partly  according  to  shape,  partly  according  to  structure  or  methods, 
of  fission,  into  genera ;  the  genera  have  been  divided,  partly  accord- 
ing to  shape  and  structure  but  chiefly  according  to  methods  and 
conditions  of  growth,  into  species.  (See  p.  281  for  families  and 
genera.  Chester's  Manual  of  Determinative  Bacteriology  is^  the 
most  useful  of  the  works  in  English  for  the  recognition  of  species.) 
But  besides  this  formal  classification,  now  becoming  slowly  ac- 
cepted, a  rougher  classification  has  been  in  use  for  many  years,  and 
is  still  largely  employed.  This  informal  classification  furnishes 
many  of  the  names  in  common  use  and  follows  here. 

LOWER  BACTERIA. 

Coccus  (from  Greek,  kokkus,  a  berry)— spheroidal  bacteria  (plural, 
cocci). 

Micrococcus — a  synonym  of  coccus. 

Diplococcus— a  coccus,  the  individuals  of  which  are  generally  at- 
tached together  in  pairs. 

Staphylococcus— a  coccus  arranged  chiefly  in  clusters. 

Streptococcus— a  coccus  arranged  chiefly  in  chains. 

Tetracoccus— a  coccus  arranged  chiefly  in  flat  groups  of  four  or 

more. 
Sarcina— a  coccus  arranged  chiefly  in  cubical  packets  of  four  or 

more  to  each  side. 
Bacillus— cylindroidal  bacteria,  straight  or  curved,  but  not  spiral 

(plural,  bacilli). 
— diplobacillus— a  bacillus  arranged  chiefly  in  pairs. 
— streptobacillus— a  bacillus  arranged  chiefly  in  chains. 


238  CLEAN  MILK 

Spirillum — cylindroidal  bacteria,  having  a  spiral  twist.  (Plural., 
spirilla.)  Very  often  the  spiral  twist  is  so  slight,  that  single 
individuals  appear  like  commas — hence  the  term  comma  bacil- 
lus, which  really  indicates  a  short  spirillum.  When  in  chains, 
however,  the  spiral  twist  is  very  evident. 

HIGHER  BACTERIA. 

The  much  elongated  or  filamentous  forms,  included  in  the 
Migula-Chester  classification,  as  streptothrix  and  chlamydo-bac- 
teriacae.  ( Note. — The  "  mycobacterium  "  of  this  classification  is 
still  often  regarded  and  spoken  of  as  "  bacillus.") 

Whether  bacteria  are  animal  or  vegetable  in  character  is  not 
settled — and  matters  little.  They  resemble  both  in  many  features, 
'and  differ  from  both  in  many  others.  At  first  considered  animal, 
they  were  later  believed  to  be  vegetable,  but  now  it  is  admitted  that 
their  exact  position  is  not  clear. 

Essentials  of  Bacterial  life. — All  living  bacteria  exist  in  one  of 
two  conditions,  the  active  growing  multiplying  condition  and  the 
dormant  or  quiescent  condition.  The  quiescent  condition  is  reached 
as  the  result  of  food  exhaustion  or  poisoning  with  their  own  excreta, 
drying  or  other  unfavorable  conditions ;  those  bacteria  which  form 
spores  have  therefore  two  quiescent  conditions,  the  spore,  and  the 
quiescent  condition  common  to  all  bacterial  cell.  The  dormant  c<  ad- 
dition of  the  non-spore-bearing  bacterial  cell,  due  to  self-poisoning 
from  its  excreta,  is  likely  to  terminate  in  the  death  of  the  organism 
and  its  destruction  by  its  own  products  (autolysis)  if  the  material  in 
which  it  lies  remains  moist:  if  drying  occurs,  however,  before  the 
death  of  the  cell,  it  will  become  dormant  but  remain  alive  and  re- 
sistant to  outside  influences  for  considerable  periods,  returning  to 
the  active  condition  if  it  reaches  favorable  surroundings;  but  the 
quiescent  condition  of  the  cell  is  not  so  resistant  as  the  spore  state. 


ESSENTIALS  OF  MILK  BACTERIOLOGY  239 

Spores  are  found  when  drying  is  slow :  if  drying  occurs  rapidly,  the 
adult  form  goes  into  the  quiescent  condition  directly. 

What  are  the  conditions  favorable  to  bacterial  growth  ?  Suit- 
able food  (which  includes  amongst  other  things  a  suitable  con- 
centration, and  a  neutral  or  nearly  neutral  reaction)  ;  suitable  tem- 
perature ;  suitable  atmosphere ;  high  humidity  and  darkness. 

Suitable  Food. — In  general,  bacteria  use  as  foods  all  waste 
products  of  animal  or  vegetable  life  and  the  dead  materials  of  the 
animal  or  vegetable  body;  some  bacteria,  however,  can  grow  in 
wholly  inorganic  solutions  and  some  refuse  to  grow  except  in. 
such  solutions.  The  food  must  not  be  present  in  too  great  a 
proportion  to  the  water  present  (i.  e.,  the  concentration  must  be 
low),  and  there  must  be  only  small  amounts  of  free  acid  or  alkali. 
(See  media  used  in  bacteriology,  p.  264.)  Bacterial  food,  in  suitable 
condition  as  to  concentration,  reaction,  and  absence  of  anything 
injurious  to  bacterial  life,  i.  e.,  ready  for  bacterial  use,  is  called 
medium  (plural,  media). 

Suitable  Temperature. — Most  bacteria  grow  best  at  about 
200  C.  to  400  C. ;  some  prefer  the  neighborhood  of  220  C.  (room 
temperature),  some  370  C.  (body  temperature),  others  refuse  to 
grow  except  at  or  about  one  temperature,  220  or  370  C.  as  the  case 
may  be.  Species  are  known  which  flourish  best  at  o°  C. ;  others 
which  flourish  best  at  6o°  to  700  C.  (hot  springs — manure).  The 
laboratory  incubator  is  usually  regulated  to  run  at  370  to  380  C. 

Suitable  Atmosphere. — Some  bacteria  grow  only  in  the  pres- 
ence of  free  oxygen  (strict  aerobes)  ;  some  only  in  the  absence 
of  oxygen  (strict  anaerobes) ;  many  grow  equally  well  under 
either  condition;  or  grow  under  both  conditions,  preferring  one, 
however  (facultative  aerobes  or  anaerobes).  Bacteria  grown  in  the 
laboratory  without  special  precautions  to  exclude  air  must  neces- 
sarily be  aerobic,  strict  or  facultative. 


24o  CLEAN  MILK 

High  Humidity. — All  bacteria  in  the  active  state  require  the 
presence  of  a  great  proportion  of  water :  water  dissolves  their  foods, 
dilutes  their  excreta,  and  acts  as  a  vehicle  for  their  movements;  but 
above  all,  water  is  necessary  for  the  passage  of  food  materials  in- 
ward through  the  cell  wall  and  for  the  passage  of  excreta  outward. 
"Water  forms  90%  or  more  of  the  ordinary  laboratory  media.  To 
prevent  concentration  of  the  media  by  evaporation  in  the  incubator, 
the  tubes  may  be  sealed,  or,  more  conveniently,  water  kept  in  bowls, 
etc.,  in  the  incubator. 

Darkness. — Unlike  most  other  living  things,  animal  and  vege- 
table, direct  sunlight  is  fatal  to  bacteria  in  a  short  time,  diffuse  sun- 
light in  a  longer  time ;  absolute  darkness  favoring  them  most.  The 
incubator,  and,  in  fact,  all  containers  used  for  bacterial  cultures, 
should  be  absolutely  dark. 

Identification. — The  recognition  of  a  given  bacterium  as  be- 
longing to  a  certain  species  involves : 

1  St.  Isolation — by  plating  and  selecting  colonies  for  reinocu- 
lation  (see  p.  256).  1 

2nd.  Working  out  the  characteristics  of  the  isolated  cultures — 
preferably  following  the  form  suggested  by  the  Soc.  Am.  Bact. 
(see  p.  282). 

3rd.  The  comparison  of  the  features  thus  determined  with 
those  already  described  by  other  workers,  as  in  Chester's  Manual, 
or  similar  tabulated  descriptions.  Certain  well  known  bacteria 
(B.  coli,  B.  tuberculosis,  streptococci,  etc.)  can  be  determined  by 
certain  special  tests  without  doing  the  elaborate  work  in  full  above: 
outlined.     These  tests  are  described  in  their  proper  places. 


CHAPTER  XI 


QUANTITATIVE  BACTERIAL  ANALYSIS  OF  MILK 


Significance  of  Bacterial  Counts. — The.  bacterial  count  means 
the  numerical  determination  of  the  "  growable  bacteria"  (/.  c., 
growable  under  the  circumstances  of  the  test  as  to  medium,  tem- 
perature, humidity,  darkness,  presence  or  absence  of  oxygen,  and 
length  of  time  allowed  for  growth)  in  the  sample  examined,  ex- 
pressed as  "  number  of  bacteria  per  c.c." 

Bacteria  cannot  be  accurately  counted  directly  under  the 
microscope;  except  when  present  in  such  immense  numbers  that 
(Winslow;  Slack)  the  merest  estimate  alone  is  required.  Such  a 
method  is  not  practical  for  certified  or  even  inspected  milk,  although 
used  with  success  for  standards  of  500,000;  hence  the  count  is 
made  by  plating  the  original  sample  or  dilutions  therefrom,  i.  e.,. 
mixing  them  with  melted  nutrient  jelly,  pouring  the  mixture  into  a 
flat  dish,  and  after  cooling  the  jelly,  allowing  growth  to  take  place. 
The  individual  bacteria,  held  apart  by  the  jelly,  develop,  producing 
little  aggregations  of  their  descendants  (colonies)  ;  and  since  each 
bacterium  produces  but  one  such  colony,  a  count  of  the  colonies 
indicates  the  number  of  the  bacteria  originally  present.  Thus,  if 
two  hundred  (growable)  bacteria  are  present  in  the  water,  etc., 
which  is  mixed  with  the  melted  jelly,  200  colonies,  or  one  for  each 
bacterium,  should  grow  in  the  plate.  It  has  been  found  by  experi- 
ence and  experiment  that  the  ordinary  "  agar  plate  "  will  not  support 

241 


242  CLE  AX  MILK 

the  growth  of  more  than'200  bacterial  colonies  of  countable  size, 
without  suppression  of  some  of  the  weaker  forms.  Should  there 
be  in  the  material  (milk,  water,  etc.)  mixed  with  the  standard  10 
c.c.  of  jelly  a  very  large  number  of  growable  bacteria,  say  2,000,000, 
the  colonies  produced  would  not  generally  greatly  exceed  10,000 
to  20,000  and  these  would  be  exceedingly  small  colonies — barely 
visible  to  the  naked  eye.  In  other  words,  placing  2,000,000  bac- 
teria in  10  c.  c.  of  medium  is  like  planting  a  thousand  grains  of  corn 
in  a  flower-pot  full  of  earth — only  a  very  few  of  the  strongest  and 
most  favorably  situated  will  survive  and  grow  up.  To  grow  from 
2,000,000  bacteria  successfully,  2,000.000  separate  colonies,  they 
should  be  planted  in  100,000  c.c.  of  jelly — a  totally  impracticable 
amount.  Hence  the  practice  is  to  reduce  the  number  of  bacteria 
plated,  rather  than  to  increase  the  food,  until  the  due  proportion 
of  200  bacteria  per  10  c.c.  of  medium  is  reached,  at  which  point  all 
present  capable  of  growing  at  all  have  freedom  to  grow,  without 
the  weaker  suffering  from  the  competition  of  the  stronger  forms. 
To  secure  this  end,  samples  containing  large  numbers  of  bacteria 
per  c.c.  must  be  plated  in  such  a  manner  that  only  such  very  small 
fractions  of  a  whole  c.c.  are  placed  in  each  plate  as  will  contain 
but  200  bacteria  per  fraction.  It  is  of  course  impossible  to  de- 
termine accurately  what  number  of  bacteria  are  present  in  a  given 
sample  before  plating  (except  by  Slack's  preliminary  miscroscopic 
count)  ;  otherwise,  why  make  a  plate  count?  Hence  it  is  impossible 
to  determine  exactly  what  fraction  of  1  c.c.  to  use  in  order  to  secure 
200  bacteria  per  plate.  The  practice  is  therefore  to  plate  several 
different  fractions  (say  i/ioc.c,  i/iooc.c,  1/1000  c.c,  etc.)  of  the 
original  sample,  and  to  select  that  plate  which  gives  40 — 200  bacteria 
as  the  one  which  represents  the  true  number  of  bacteria.  The  num- 
ber of  colonies  in  this  plate,  multiplied  by  the  dilution  it  represents, 
gives  the  number  per  c.c 

Thus — If  2,000,000  bacteria  (growable)  exist  in  each  c.c  of 


QUANTITATIVE  BACTERIAL  ANALYSIS         243 

a  given  milk  sample,  and  if  successive  decimal  fractions  of  1  c.c. 
-are  taken  for  plating,  the  plates  will  contain  as  follows: 

Plate  No.      1234  5  6 

1  c.  c.         1/10     1/100       1/1,000     1/10,000  1/100,000 
The  number  of  bacteria  thus  placed  in  each  plate  will  be 

2,000,000  200,000     20,000       2,000  200  20 

But  the  colonies  produced  by  these  will  be  (approximately) 

l15 

10,000   9,000   7,000   1,400    200    <  25 

(30 

Knowing  that  plates  containing  over  200  do  not  develop  a  colony 
for  each  growable  bacterium  placed  in  it,  but  only  for  the  strongest 
ones,  reject  all  but  plate  No.  5.  This  contains  200  colonies;  they 
developed  from  1/10,000  c.c.  of  the  sample;  hence  1  c.c.  of  the 
sample  must  contain  200  X  10,000  =  2,000,000  colonies. 

On  the  other  hand,  counts  below  40  colonies  per  plate  are  also 
unreliable,  from  the  mechanical  difficulties  attendant  on  removing 
so  small  a  number  accurately  from  a  mixture.  If  a  dilution  is 
made  so  low  as  to  secure  only  10 — 30  colonies  per  plate  (as  in 
No.  6  plate  above),  the  chances  of  any  one  plate  showing  a  number 
of  colonies  truly  corresponding  with  the  dilution  made  is  rather 
small.  Plate  No.  6  is  so  diluted  that  the  proper  proportion  is 
only  20  colonies  per  plate,  but  the  chances  are  that  15  or  30  or 
some  other  number  rather  than  20  (but  not  far  from  it)  will  actu- 
ally grow.  It  will  be  seen  that  the  error  introduced  by  considering 
such  low  dilution  accurate  would  be  in  the  case  given  reporting 
of  a  count  of  1,500,000,  2,500,000  or  3,000,000,  whereas  the  true 
count  is  2,000,000. 

It  is  quite  important  to  thoroughly  understand  this  principle, 
as  great  errors  in  reporting  counts  may  obviously  be  made  if  they 
are  neglected.     Thus,  if  seven  different  laboratories  report  on  a, 


244  CLEAN  MILK 

given  milk  supply  using  identical  technique  and  each  securing  the- 
same  set  of  counts  from  the  dilutions  made,  but  differing  as- 
to  calculation  of  count,  they  might  report  from  such  figures  as  the 
above,  no  less  than  seven  different  results,  all  justified  by  existing 
(but  erroneous)  methods  of  calculation.  Owing  to  the  fact  that 
it  is  not  usually  the  custom  to  make  more  than  two  or  three  dilu- 
tions, and  these  not  necessarily  the  same,  the  actual  number  of  pos- 
sible reports  from  the  same  milk  if  badly  contaminated  is  about 
fifteen,  ranging  from  25,000  to  2,000,000. 

If  different  techniques  are  used,  especially  as  regards  medium, 
temperature  and  time  of  incubation,  results  differing  from  50%  to^ 
200%  may  be  obtained  from  the  same  sample,  even  using  the  same 
methods  of  calculation.  Hence  the  absolutely  essential  need  for 
uniformity  of  technique  and  uniformity  of  calculation.  Neither 
one  alone  will  give  figures  of  any  moment  whatever. 

Interpretation  of  Count. — Attention  to  condition  of  cow,  clean- 
liness, cold,  and  quickness  in  transportation,  as  described  elsewhere 
in  this  book,  will  alone  secure  low  count  milk.  Failure  in  any 
one  of  these  essentials  is  faithfully  recorded  by  the  bacterial  count. 
Indeed,  the  bacteria  in  milk  may  be  regarded,  from  the  standpoint 
of  the  sanitary  milk  inspector,  as  a  tell-tale  or  automatic  register, 
of  the  treatment  the  sample  tested  has  received  in  these  regards. 
Neglect  of  any  necessary  precaution  is  written  down  by  these  faith- 
ful "  recording  angels  "  for  the  bacteriologist  to  read. 

The  simple  count,  taken  alone,  while  it  gives  the  sum  total 
effect  of  whatever  mistreatment  the  milk  may  have  received,  does 
not  indicate  what  the  mistreatment  was,  /.  e.,  whether  it  lay  in 
neglect  of  the  cow,  admission  of  dirt,  high  temperature,  or  lapse 
of  time.  If  the  differentiation  of  these  is  desired,  it  may  be 
achieved  only  by  learning  the  history  of  the  milk,  and  thus  deter- 
mining which  factor  or  factors  suffered  neglect.  If  the  history  of 
the  milk  shows  delay  in  transportation,  especially  with  lack  of  cool— 


QUANTITATIVE  BACTERIAL  ANALYSIS         245 

-Ing  in  transit,  a  dirty,  dusty  barn,  utensils,  or  animal,  or  a  gargety 
cow,  the  count  may  be  attributed  to  these. 

Confirmation  of  these  may  be  obtained  in  two  directions — the 
lieight  of  the  count  and  the  character  of  the  bacteria  present,  the 
latter  involving  considerable  additional  bacteriological  work  for  its 
final  determination.  This  outline  cannot  be  considered  wholly  final, 
but  as  yielding  strong  indications,  which  should  be  confirmed  by 
actual  investigation. 

A  high  count,  almost  wholly  consisting  of  lactic  acid  bacilli  = 
probability  of  slow  transit,  at  a  temperature  of  6o° — 8o°.  (The 
acidity  of  such  a  sample  would  be  high.) 

A  high  count,  with  a  variety  of  bacteria,  lactic  acid  bacilli  not 
prominent  =  probability  of  slow  transit  at  low  temperatures,  300  ta 
500.     (The  acidity  of  the  sample  would  be  moderate.) 

A  high  count,  showing  many  spore-forming  bacteria,  without 
great  acidity=probability  of  pasteurization,  followed  by  too  long- 
keeping  at  too  high  a  temperature. 

A  high  count,  showing  a  very  large  variety  of  forms,  especially 
fluorescent  and  chromogenic  forms,  suggests  extensive  contamina- 
tion from  dust,  etc.,  or  possibly  from  watering.  If  the  milk  is  fresh 
and  not  very  acid,  the  "  dirt  "  origin  of  the  bacteria  is  largely 
confirmed. 

A  high  count,  consisting  chiefly  of  streptococcus  colonies, 
points  to  a  gargety  condition  in  the  cow. 

A  low  plate  count,  since  it  gives  the  living  bacteria,  combined 
with  a  high  direct  count  by  Slack's  method,  since  this  gives  dead 
as  well  as  living  bacteria,  suggests  recent  pasteurization  of  a  high 
count  milk. 

The  propositions  converse  to  the  above  will  not  always  hold 
true,  however,  and  many  combinations  arise,  the  interpretation  of 
which  cannot  be  made  easily,  since  frequently  many  of  the  factors 
.given  operate  at  one  time,  but  in  different  proportions  in  different 
cases.     Only  the  simpler  basic  combinations  are  stated  here.     The 


246  CLEAN  MILK 

milk  bacteriologist  engaged  in  daily  examinations  must  learn  to 
deduce  for  himself  the  more  intricate  inter-relations  which  arise. 

The  determination  of  species  is  difficult  and  intricate  work,  to- 
be  attempted  on  a  large  scale  only  by  those  who  have  much  time  and 
energy  to  devote  to  it.  The  required  tests  are  given  on  page  282. 
The  careful  working  out  of  a  culture  isolated  from  a  plate  on  the 
various  media,  by  the  methods  there  outlined,  and  comparison  of 
the  results  with  some  text-book  giving  the  various  species  in 
groups  for  identification,  is  the  only  wholly  satisfactory  way. 

Streptococci  may  be  recognized  by  the  method  outlined  in 
standard  methods  of  milk  analysis.*  Tubercle  bacilli  will  not  be 
found  in  plates,  being  slow  growers  at  best  and  plain  nutrient  agar 
being  a  very  poor  medium  for  their  growth.  They  may  be  found 
by  staining  the  cream  or  sediment  of  centrifugalized  milk  by  the 
Ziehl-Nielsen  method,  which  shows  them  red  on  a  blue  ground. 
Failing  this,  inoculations  into  guinea  pigs  from  the  same  sources, 
should  be  tried. 

Objections  to  the  Numerical  Standard. — 1.  That  the  sample 
examined  can  never  be  condemned  in  time  to  prevent  use  of  the 
milk  by  the  consumer,  since  the  results  are  not  available  for  at  least 
24  hours,  hence  only  the  dairy  which  supplied  that  sample  can  be 
beld  responsible  in  a  general  way  for  putting  it  on  the  market.  Of 
course  this  objection  applies  to  any  system  of  analysis  which  takes 
more  than  a  few  minutes — such  as  the  mere  testing  of  temperature 
(as  advocated  in  New  York)  or  the  microscopic  count  advocated 
by  Slack. 

It  has  been  shown  conclusively  (Boston  Board  of  Health  Re- 
ports) that  the  temperature  test  is  absolutely  fallacious  in  distin- 
guishing high  and  low  count  milk,  since  it  indicates  only  the  tem- 
perature at  the  moment  of  the  test — not  how  long  that  temperature 


*  Very  small  white  colonies,  on  agar  plates  after  24  hours,  which  yield  diplococcL 
in  smears,  but  which,  transferred  to  broth  at  37    C,  yield  chains  of  cocci. 


QUANTITATIVE  BACTERIAL  ANALYSIS         247 

"has  existed.  A  logical  application  of  the  temperature  test  would 
require  a  test  at  each  dairy,  another  at  each  receiving-  and  shipping 
station,  and  another  at  the  wagon,  besides  information  as  to  con- 
ditions en  route  and  in  storage.  Slack's  method,  while  applicable 
to  comparatively  lenient  standards,  such  as  500,000  per  ex.,  is  not 
sufficiently  accurate  for  more  severe  standards,  such  as  those  re- 
quired for  inspected  (100,000  per  c.c.)  and  certified  (10,000  per 
c.c. )  milk. 

Since  the  very  object  of  the  test  is,  not  to  determine  the 
harm  fulness  of  a  particular  sample,  but  how  well  the  dairy  it  came 
from  is  supervising  every  step  in  the  production  of  good  milk, 
the  objections  on  these  scores  are  entirely  misplaced. 

2.  The  condemning  of  clean  milk  kept  too  long  at  too  high  a 
temperature,  as  against  the  passing  of  dirty  milk,  shrewdly  cooled 
at  once  to  a  low  point. 

This  objection  would  have  some  weight,  if  it  were  true.  How- 
ever, the  dirty  milk  can  be  detected  despite  the  cooling,  since  neg- 
lect of  this  one  factor  will  raise  the  count;  while  the  clean  milk, 
poorly  iced  and  long  delayed,  should  be  condemned,  since  its  vir- 
tues in  one  direction  are  offset  by  neglect  in  another.  It  has  been 
demonstrated  again  and  again,  even  by  the  objectors,  that  dirty 
methods  result  in  an  immediate  and  enormous  rise  in  the  count, 
and  while  subsequent  development  may  be  restrained  by  cooling, 
the  initial  rise  cannot  be  concealed. 

3.  That  the  numerical  count  cannot  ensure  the  whoJesome- 
ness  of  milk.  This  is  perfectly  true.  A  milk  containing  a  count  of 
500,000  lactic  acid  bacilli  and  hence  barely  passable  as  "  market 
milk  "  by  the  most  lenient  standards,  may  be  absolutely  harmless ; 
while  a  milk  of  5,000  count,  hence  well  under  the  highest  standards 
for  certified  milk,  may  cause  infinite  harm  should  all  or  even  one- 
tenth  of  these  be  typhoid  bacilli. 

Such  an  argument,  however,  is  beside  the  point.  No  one  ob- 
jects to  inspection  for  adulteration,  watering,  etc.,  although  admit- 


248  CLEAX  MILK 

tedly  nine-tenths  of  such  watering  is  perfectly  harmless.  The  ob- 
ject of  the  numerical  standard  is  not  primarily  to  secure  a  low 
count,  but  fresh,  sweet,  pure  milk,  from  healthy  cozes.  No  dealer 
failing  in  any  one  of  these  features  can  secure  a  low  count  in  milk, 
and  his  failures,  undetectable  otherwise  without  tremendous  cost 
and  labor  in  inspection,  can  be  determined  very  simply  and  accu- 
rately by  the  numerical  standard.  Such  a  standard  will  not  secure 
the  exclusion  of  individual  accidents — no  method  will  do  that— but 
ir.  will  ensure  and  compel  a  very  high  average  of  freedom  from  un- 
desirable conditions. 

4.  That  the  bacterial  count  cannot  be  legally  enforced  is  a 
matter  easily  offset  by  the  fact  that  it  has  been  legally  enforced 
in  Boston.  It  is  true  that  in  the  chaotic  condition  lately  exist- 
ing as  to  technique  and  methods  of  calculation,  it  would  have 
been,  and  for  some  time  yet  will  be,  easy  to  secure  contradictory 
reports  from  "  experts,"  or  to  produce  evidence  of  the  unstandard- 
ized  methods  existing  in  too  many  laboratories.  With  a  general 
recognition  amongst  laboratory  men  and  public  health  executives 
that  the  numerical  standard  cannot  properly  be  stated  merely  as 
a  fixed  figure,  but  as  a  fixed  figure  obtained  by  standard  methods 
of  technique  and  calculation,  these  difficulties  will  quickly  disap- 
pear. A  great  deal  has  already  been  accomplished  through  the 
agency  chiefly  of  the  bacterial  count,  and  more  will  be,  as  its 
strength  and  weaknesses  become  better  known.  But  the  bacterial 
count  is  simply  a  method  of  inspection,  readily  and  easily  applied 
to  great  numbers  of  samples  in  a  short  time,  with  but  few  men. 
It  is  not  in  itself  an  automatic  reformer  of  the  dairy,  the  milk 
handler  or  the  milk  peddler.  It  is  a  test,  like  litmus,  to  determine 
results :  it  is  not  except  indirectly  a  producer  of  those  results. 

A  most  useful  application  of  the  bacterial  count  is  made  by 
those  large  milk  concerns,  who  through  their  own  private  bacter- 
iological laboratories,  exercise  supervision  over  the  dairies  supplying 


QUANTITATIVE  BACTERIAL  ANALYSIS         249 

rnilk  to  them  in  a  direct  individual  manner  impossible  to  large  mun- 
icipalities. 

Another  application,  and  one  likely  to  develop  rapidly  in  the 
future,  is  the  establishment  of  bacteriological  laboratories  at  the 
dairies  themselves,  so  that  each  dairy  may  control  its  own  product 
in  the  first  place.  Naturally  this  is  only  likely  to  be  done  where 
the  dairy  is  a  large  one,  and  is  devoted  to  the  production  of  clean 
milk  as  a  business. 

Standard  Counts  for  Milk. — Experience  and  experiment  have 
crystallized  the  opinions  held  by  most  sanitarians  into  a  set  of 
standards  voiced  by  A.  D.  Melvin,  Chief  of  the  Department  of 
Agriculture,  as  follows:  for  certified  milk,  a  limit  of  10,000  per 
c.c.  when  delivered  to  the  consumer;  for  inspected  milk,  a  limit  of 
100,000  per  c.c.  when  delivered  to  the  consumer.  All  milk  above 
this  point  should  be  pasteurized  before  sale  is  permitted,  according- 
to  some  authorities.  This  at  present  is  an  academic  requirement, 
especially  in  large  cities.  Hence  Boston  and  some  other  cities  and 
the  State  of  Minnesota  permit  500,000  per  c.c.  in  market  milk. 

EXAMINATIONS  FOR  "  PUS  "  IN  MILK. 

This  subject  has  been  so  much  discussed  and  so  many  methods 
and  objections  to  methods  have  been  proposed  that  only  a  much 
more  extended  account  than  is  possible  here  could  adequately  treat 
the  subject.  At  present  writing  the  tendency  is  to  consider  the  test 
of  chief  value  for  municipal  milk  inspection  and  analysis,  where 
the  actual  routine  veterinary  examination  of  all  cows  cannot  be  done. 
The  finding  of  an  unusually  high  cellular  content  by  any  method 
should  lead  to  investigation  of  the  dairy  supplying  the  milk  in 
question.  Often  cows  suffering  from  mammitis  or  garget  are 
found  in  this  way.  On  the  other  hand,  it  has  apparently  been  well 
•established  that  cows  giving  unusually  high  cellular  content  have 
been  found  in  which  no  veterinary  examination,  however  careful, 


250  CLEAN  MILK 

could  detect  any  lesion  or  disease.  The  Committee  on  Standard 
Methods,  already  quoted,  gives  only  guarded  recommendations  on 
this  point,  awaiting  further  evidence.  Those  who  wish  to  follow 
the  literature  will  find  an  excellent  bibliography  in  the  Reports  of 
the  Committee  (the  second  report  will  now  soon  appear). 

EXAMINATIONS   FOR  STREPTOCOCCI  IN   MILK. 

The  smear  method  of  Slack  (see  Report  of  Committee  on 
Standard  Method;  also  used  for  the  detection  of  pus  in  milk) 
or  the  recognition  and  isolation  of  colonies  of  streptococci  from 
plates  made  for  counting  purposes  may  be  followed.  The  signifi- 
cance of  streptococci  in  milk  is  almost  as  much  in  dispute  as  is  the 
significance  of  "  pus."  In  general  it  may  be  stated  that  any  num- 
ber exceeding  the  ordinary  number  found  in  milk  calls  for  investi- 
gation of  the  dairy  supplying  the  milk,  with  individual  inspection 
of  the  cows  for  mammitis,  etc.,  and  critical  inspection  of  methods 
relating  to  exclusion  of  dirt,  particularly  of  manure,  from  the  milk. 
The  standards  adopted  for  the  maximum  number  of  streptococci 
which  may  be  found  without  calling  for  such  investigations,  like  the 
standards  for  "  pus,"  have  varied  much  in  different  places. 

STANDARDS    FOR    PUS   AND    STREPTOCOCCI.* 

Standards  adopted  tentatively  in  Boston  have  been  followed 
elsewhere  and,  while  no  final  value  can  be  claimed  for  them,  are 
quoted  below,  from  a  private  communication  made  by  Dr.  F.  H. 
Slack,  Director  of  the  Boston  Board  of  Health  Bacteriological 
Laboratory.  The  truth  seems  to  be  that  while  injustice  may  some- 
times be  done  to  the  farmer  in  condemning  a  milk  for  "  pus  "  when 
as  a  matter  of  fact  the  milk  may  come  from  a  normal  cow  con- 
tributing a  number  of  leucocytes  to  the  milk  in  excess  of  those 
usually  contributed  by  most  cows,  yet  the  failure  to  insist  on  such  a 


*  For  proposed  standards,  see  pp.  295,  349. 


QUANTITATIVE  BACTERIAL  ANALYSIS         251 

standard  more  often  does  injustice  to  the  consumer,  since  a  high 
leucocytic  count  usually  indicates  an  abnormal  cow. 

COLLECTION  OF  SAMPLES. 

'(From  Preliminary  Report  of  Committee  on  Standard  Methods.) 

Quantity  of  Milk  Required  for  Analysis. — The  minimum 
quantity  of  milk  necessary  for  making  an  ordinary  bacteriological 
examination  is  ten  cubic  centimeters.  When  making  examinations 
for  cerified  milk,  if  possible  a  pint  or  quart  bottle  should  be  taken 
and  brought  to  the  laboratory  unopened. 

Collecting  Apparatus. — In  collecting  milk  samples  for  bac- 
teriological examination  it  is  essential  that  the  sample  be  taken 
and  kept  in  such  a  manner  as  to  prevent  either  any  addition 
of  bacteria  from  without  or  multiplication  of  the  bacteria  originally 
present.  Bottles,  tubes,  pipettes,  etc.,  used  in  the  collection  of 
samples,  besides  being  washed,  shall  be  sterilized  with  dry  heat  for 
an  hour  at  or  about  1600  C,  or  to  the  charring  point  of  cotton. 

In  the  selection  of  "  certified  milk  "  samples  it  is  recommended 
wherever  possible  that  an  unopened  bottle  be  taken,  placed  in  a  suit- 
ably iced  case  and  brought  at  once  to  the  laboratory. 

Samples  of  "  market  milk  "  may  be  collected  as  are  water 
samples,  in  sterile,  wide-mouthed,  glass-stoppered  four-ounce  bot- 
tles; the  case  in  which  they  are  carried  being  well  iced.  The  prin- 
cipal difficulty  encountered  in  this  method  is  in  transferring  the 
sample  from  the  original  container  to  the  bottle,  and  the  various 
string  and  wire  devices  by  means  of  which  the  bottle  is  immersed  in 
the  original  container  are  objectionable  both  on  account  of  the 
labor  of  preparing  such  an  outfit  and  also  on  account  of  the  coating 
of  milk  left  on  the  outside  of  the  bottle  when  the  sample  has  been 
taken. 

An  apparatus  designed  for  the  use  of  thirty-two  test  tubes 


252 


CLEAN  MILK 


as  containers  *  is  recommended  as  superior  to  one  designed  for 
bottles  (Fig.  62). 

It  has  been  proven  that  with  samples  kept  properly  iced 
in  this  particular  form  of  case  there  is  no  increase  of  bacterial  con- 
tent even  after  twenty-four  hours,  but  rather  a  slight  decrease,  the 
counts  varying  hardly  more  than  might  be  expected  in  duplicate 
plates.  It  is  recommended,  however,  that  examination  of  the  sam- 
ples be  proceeded  with  as  quickly  as  possible  after  the  collections 
are  made. 

Fig.  62. 


Boston  Board  of  Health — collecting  case  for  milk  samples.      (After  Conn. ) 

The  samples  are  removed  from  the  cans  with  sterilized  pipettes,  and  placed  in 
tubes.  These  are  placed  in  weighted  racks  [A)  and  put  into  the  center  compart- 
ment of  the  carrying  case. 

Identification  of  Samples. — When  bottles  are  used  identifica- 
tion numbers  should  be  etched  on  both  bottle  and  stopper.  Test 
tubes  should  be  labeled  or  etched  and  numbered. 

A  complete  record  of  the  samples  taken,  giving  date,  time, 
place,  name  of  party  from  which  sample  is  taken,  name  of  collector, 
temperature  of  milk,  character  of  original  container    (tank,  can, 


*Am.  Jour.  Pub.  Hyg.,  Nov.  '04. 


QUANTITATIVE  BACTERIAL  ANALYSIS         253; 

bottle),  etc.,  should  be  written  opposite  duplicate  numbers  in  a 
blank  book  or  pocket  card  catalogue,  or  this  information  may  be 
written  on  small  tags  and  tied  or  wired  to  the  corresponding  test 
tube  or  bottle. 

Temperature. — The  temperature  should  be  taken  immediately 
after  taking  the  sample  for  analysis,  while  the  milk  is  still  thor- 
oughly mixed. 

If  it  is  desired  to  take  the  temperature  of  "  certified  milk," 
this  should  be  done  when  the  sample  is  taken,  but  from  another 
bottle. 

A  floating  thermometer,  graduated  to  the  Fahrenheit  scale, 
is  most  convenient,  and  the  temperature  should  be  expressed  to  the 
nearest  degree.  It  is  necessary  to  standardize  the  thermometer  for 
at  least  ten  degrees  on  each  side  of  the  legal  temperature  limit. 
A  quickly  registering  thermometer  should  be  left  at  least  one  min- 
ute in  the  milk  and  read  as  soon  as  removed.  A  small  piece  of 
clean  absorbent  cotton  may  be  used  to  wipe  the  adhering  milk  from 
the  thermometer  that  the  scale  may  be  easily  seen. 

Representative  Samples. — The  collector  should  always  select 
his  own  sample,  and  care  should  be  taken  to  secure  a  sample  which, 
is  truly  representative  of  the  milk  to  be  examined. 

One  of  several  methods  of  mixing  the  milk  may  be  used,  com- 
parison having  shown  the  results  to  be  practically  the  same. 

1.  Pouring  the  milk  into  a  sterile  receptacle  and  back. 

2.  Shaking  the  milk  thoroughly  with  receptacle  turned  up- 
side down.  (This  may  be  done  where  the  can  or  bottle  is  tightly 
stoppered  or  capped  and  is  not  so  full  as  to  prevent  thorough 
agitation.) 

3.  In  open  tanks  in  stores  it  is  allowable  to  stir  thoroughly 
with  the  long-handled  dipper  generally  found  in  use. 

4.  Where  the  test  tube  collecting  case  is  used,  thoroughly  re- 
liable results  are  secured  by  first  shaking  the  can  or  bottle ;  and, 
second,  stirring  with  the  large  pipette  before  taking  the  sample,.. 


254  CLEAN  MILK 

care  being  taken  to  close  the  upper  end  of  the  pipette  with  the 
finger  so  that  no  milk  enters  until  after  the  mixing;  or  the  pipette 
may  be  emptied  after  stirring  before  the  sample  is  taken. 

5.  For  certified  milk  samples  it  is  recommended  that,  on  ar- 
rival at  the  laboratory,  the  bottle  be  opened  with  aseptic  precau- 
tions and  the  milk  thoroughly  mixed  by  pouring  back  and  forth 
between  the  original  bottle  and  a  sterile  bottle.  Another  method 
is  to  mix  as  thoroughly  as  possible  by  agitation  for  five  minutes, 
then  burn  through  the  pasteboard  stopper  with  a  hot  iron  and  re- 
move the  desired  amount  of  milk  with  a  sterile  pipette. 

THE    INTERVAL    BETWEEN    COLLECTIONS    AND    ANALYSIS. 

Generally  speaking,  the  shorter  the  time  between  the  collection 
and  examination  of  milk  samples  the  more  accurate  will  be  the 
results.  For  routine  work  the  attempt  should  be  made  to  plate 
within  four  hours  of  the  time  of  collection. 

Too  much  stress  cannot  be  laid  on  keeping  the  samples  properly 
iced  during  this  interval.  They  should  be  kept  below  400  F.,  but 
care  should  be  taken  that  they  are  not  frozen. 

DILUTIONS. 

Ordinary  potable  water,  sterilized,  may  be  used  for  dilu- 
tions. Occasionally  spore  forms  are  found  in  such  water  which 
resist  ordinary  autoclave  sterilization;  in  such  cases  distilled  water 
may  be  used  or  the  autoclave  pressure  increased.  With  dilution 
water  in  eight-ounce  bottles  calibrated  for  ninety-nine  cubic  centi- 
meters and  in  test  tubes  calibrated  for  nine  cubic  centimeters,  all  the 
necessary  dilutions  can  be  made. 

Short,  wide-mouthed  "  Blakes "  or  wide-mouthed  French 
square  bottles  are  more  easily  handled  and  more  economical  of  space 
than  other  forms  of  bottles  or  flasks. 


QUANTITATIVE  BACTERIAL  ANALYSIS         255 

Eight-ounce  bottles  are  the  best,  as  the  required  amount  of 
dilution  water  only  about  half  fills  them,  leaving  room  for  shaking. 
Long-fiber,  non-absorbent  cotton  should  be  used  for  plugs.  It  is 
well  to  use  care  in  selecting  cotton  for  this  purpose  to  avoid  short- 
fiber  or  "  dusty  "  cotton,  which  gives  a  cloud  of  lint-like  particles 
on  shaking.  Bottles  and  tubes  should  be  filled  a  little  over  the  99 
c.c.  and  9  c.c.  marks  to  allow  for  loss  during  sterilization.* 

The  dilutions  recommended  are  1/10,  1/100,1/1,000,  1/10,000, 
1/100,000  and  1/1,000,000. 

For  certified  milk  the  1/10  and  1/100  dilutions  should  be  used, 
while  the  1/10,000  will  usually  be  found  best  for  market  milk. 

The  1/10  dilution  is  prepared  by  shaking  the  milk  sample 
twenty-five  times  and  then  transferring  1  c.c.  of  the  milk  to  a  test 
tube  containing  9  c.c.  of  sterile  water. 

The  1/100  dilution  is  prepared  in  the  same  way,  except  that 
a  bottle  with  99  c.c.  of  sterile  water  is  substituted  for  the  test  tube. 

The  1/1,000  dilution  is  prepared  by  first  making  the  1/100 
dilution,  shaking  twenty-five  times  and  transferring  1  c.c.  of  the  dil- 
ution to  a  test  tube  containing  9  c.c.  of  sterile  water. 

The  1/10,000,  1/100,000  and  1/1,000,000  dilutions  are  made 
in  the  same  manner  by  dilutions  of  the  1/100,  1/1,000  and 
1/10,000  dilutions,  1  c.c.  to  99  c.c.  of  sterile  water. 

It  is  recommended  that  that  dilution  be  used  which  will  pro- 
duce about  two  hundred  colonies  to  a  plate,  ranging  from  40  to 
400;  where  a  1/10  dilution  exceeds  this  number  the  1/100  dilution 
is  more  accurate,  etc.  The  number  of  bacteria  present  may  if  desired 
be  approximately  estimated  before  dilutions  are  made  by  direct 
microscopic  examination  of  a  properly  prepared  sediment.  Other- 
wise it  is  necessary  to  make  a  range  of  dilutions,  thereafter  select- 


*  If  the  loss  during  sterilization  has  not  sufficed  to  bring  the  water  level  down  to  the 
marks,  sufficient  water  may  be  further  removed  with  a  sterile  pipette.  If  sterilization 
has  removed  a  little  too  much,  sufficient  sterile  water  may  be  added  with  a  sterile  pipette- 
Ordinarily,  however,  experience  will  show  how  much  to  overfill  before  sterilization,  so  that 
no  change  is  required  afterwards. 


256  CLEAN  MILK 

ing  for  record  the  count  obtained  on  that  plate  which  yields  between 
40  and  400  colonies. 

Plating  undiluted  milk  is  unreliable,  whatever  quantities  be 
used,  since  the  bacteria  are  not  so  well  separated  as  in  the  dilutions, 
and  often,  owing  to  the  crowded  conditions,  only  a  portion  of  the 
bacteria  present  will  develop  into  visible  colonies.  Moreover,  if  a 
cubic  centimeter  of  the  milk  is  used,  the  turbidity  of  the  jelly,  due 
to  the  presence  of  the  milk,  hides  the  colonies  present  from  the 
eye.* 

MEDIA. 

The  standard  medium  for  determining  the  number  of  bacteria 
in  milk  shall  for  the  present  be  agar,  made  according  to  the  recom- 
mendations of  the  Committee  on  Water  Analysis,  except  that  the 
percentage  of  agar  shall  be  1%  and  the  reaction   +  1.5. 

All  variations  from  agar  media  made  as  described  shall  be  con- 
sidered as  special  media. 

Much  work  yet  remains  to  be  done  on  media;  the  above  is 
recommended  as  giving  the  highest  and  most  uniform  counts  so 
far  as  our  comparative  work  has  extended  and  with  but  slight 
variations  is  the  medium  in  most  common  use. 

Storage  of  Media. — Media  may  be  made  up  in  quantity, 
tubed  and  stored   (preferably  in  an  ice  chamber). 

PLATING,  f 

Plating  Apparatus. — For  plating  it  is  best  to  have  a  single 
water  bath  in  which  to  melt  the  media  and  a  water-jacketed  water 
bath  for  keeping  it  at  the  proper  temperature;  a  wire  rack,  which 
should  fit  both  of  the  water  baths,  for  holding  the  media  tubes; 

*  The  old  practice  was  to  plate,  not  1  c.c.  of  a  dilution,  varying  the  dilution  to  suit 
conditions,  as  described  above,  but  to  plate  the  undiluted  sample  in  fractional  portions  of 
ace.  While  mathematically  the  same  amount  of  milk  is  plated,  whether  -j-^  c.c.  of 
undiluted  milk  or  i  c.c.  of  a  dilution  of  I  to  99  be  used,  in  practice  the  latter  is  superior, 
for  the  reasons  given  above. 

f  A  method  of  avoiding  troubles  due  to  moisture  consists  of  inverting  the  plates  and 
putting  in  the  lid  of  each  petri  dish  a  strip  of  blotting  paper  on  which  there  is  a  large 
drop  of  glycerine.  Incubate  as  directed.  (Extract  from  1908  Report  of  American 
Public  Health  Association.) 


QUANTITATIVE  BACTERIAL  ANALYSIS         257 

a  thermometer  for  recording  the  temperature  of  the  water  in  the 
water-jacketed  bath;  sterile  1  c.c.  pipettes;  sterile  petri  dishes;  and 
sterile  dilution  water  in  measured  quantities. 

For  milk  work  porous  earthenware  petri  dish  covers  (Fig.  63) 
are  much  superior  to  glass  covers,  since  they  absorb  the  excess 
moisture  from  the  agar  and  prevent  "  spreading." 

It  is  quite  essential  to  the  best  results  that  the  porous  covers 
should  be  wet  as  seldom  as  possible.  In  sterilizing  them  the  process 
should  be  prolonged  beyond  the  time  necessary  to  kill  the  organisms 
an  order  that  the  covers  may  be  thoroughly  dry. 

Straight-sided    1    c.c.   pipettes  are  more   easily  handled  than 


Fig-  63. 


Petri  Dishc 


those  with  bulbs;  they  may  be  made  from  ordinary  glass  tubing 
about  3/16  of  an  inch  in  diameter  and  calibrated  in  the  laboratory. 
They  should  be  made  about  10  inches  in  length. 

Plating  Technique. — The  agar  after  melting  should  be  kept 
in  the  water-jacketed  water  bath  between  400  C.  and  45  °  C.  for 
at  least  fifteen  minutes  before  using,  to  make  sure  that  the  agar 
itself  has  reached  the  temperature  of  the  surrounding  water.  If 
used  too  warm  the  heat  may  destroy  some  of  the  bacteria  or  retard 
their  growth.  Below  this  temperature  the  agar  tends  quickly  to 
solidify. 

For  routine  work  in  cities  in  order  to  bring  down  the  actual 
number  of  colonies  in  a  plate  around  the  standard  of  two  hundred, 


^58 


CLEAN  MILK 


it  is  well  to  use  a  dilution  of  1/10,000.     To  make  this  dilution,  use 
Fig.  64.  two  bottles  of  sterile  water  each  containing  99  c.c. 

Shake  the  milk  sample  twenty-five  times,  then  with  a 
sterile  pipette  remove  1  c.c,  put  into  the  first  dilution  water 
and  rinse  the  pipette  by  drawing  dilution  water  to  the  mark 
and  expelling;  this  gives  a  dilution  of  1  to  100. 

Shake  the  first  dilution  twenty-five  times,  then  with  a 
fresh  sterile  pipette  remove  1  c.c,  put  into  the  second  dilu- 
tion water,  rinsing  the  pipette  to  the  mark  as  before;  this 
gives  a  dilution  of  1  to  10,000.  Shake  the  second  dilution 
twenty-five  times,  then  with  a  sterile  pipette  remove  1  c.c 
and  put  it  into  the  petri  dish,  using  care  to  raise  the  cover 
only  so  far  as  necessary  to  insert  the  end  of  the  pipette. 

Taking  a  tube  of  agar  from  the  water  bath,  wipe  the 
water  from  outside  the  tube  with  a  piece  of  cloth,  remove 
the  plug,  pass  the  mouth  of  the  tube  through  the  flame,  and 
pour  the  agar  into  the  plate,  using  the  same  care  as  before 
to  avoid  exposure  of  the  plate  contents  to  the  air. 

Carefully  and  thoroughly  mix  the  agar  and  diluted 
milk  in  the  petri  dish  by  a  rotary  motion,  avoiding  the  form- 
ation of  air  bubbles  or  slopping  the  agar,  and  after  allow- 
ing the  agar  to  harden  for  at  least  fifteen  minutes  at  room 
temperature  place  the  dish  bottom  down  in  the  incubator. 
The  practice  of  mixing  the  diluted  milk  with  the  agar  in  the 
tube  leaving  a  certain  portion  of  the  bacteria  unplated,  is 
not  recommended  by  the  Committee. 

Controls. — Plating  should  always  be  checked  by  con- 
trols. A  blank  plate  should  be  made  with  each  set  of  milk 
plates  for  control  of  the  water,  petri  dishes,  pipettes,  etc 

For  control  on  technique  of  plating  it  is  recommended 
that  for  work  on  "  market  milk,"  duplicates  be  made  each 
day  on  several  plates. 
Certified  milk  "  should  always  be  plated  in  duplicate,  and 


1  c.  c.  pip- 
ettes in- 
closed in 
tubes  for 
steriliz- 
ing. 


QUANTITATIVE  BACTERIAL  ANALYSIS         259 

where  possible  it  is  well  to  have  one  man's  work  occasionally  checked 
by  another. 

Unless  duplicate  plates  show  as  a  rule  approximately  the  same 
count,  the  worker  should  see  if  there  is  error  in  his  technique. 

Racks  are  very  useful  for  stacking  the  plates  and  to  prevent 
breakage. 

Plating  should  be  done  always  in  a  place  free  from  dust  or 
currents  of  air. 

In  order  that  the  colonies  may  have  sufficient  food  for  proper 
development,  10  c.c.  of  agar  shall  be  used  for  each  plate.  In  plat- 
ing a  large  number  of  samples  at  one  time  the  dilution  and  transfer 
of  diluted  milk  to  the  plates  may  be  done  for  four  or  eight  samples, 
then  the  agar  poured,  one  tube  to  each  plate,  then  another  eight 
samples  diluted,  etc. 

INCUBATION.* 

Concerning  incubation  two  methods  are  at  present  in  use. 
Three-fifths  of  the  laboratory  workers  consulted  recommended  in- 
cubation at  370  C.  for  twenty-four  hours  with  saturated  atmos- 
phere, the  remaining  two-fifths  allowed  varying  lengths  of  time 
at  different  degrees  of  room  temperature  and  at  whatever  degree 
of  humidity  happened  to  obtain. 

When  considering  these  two  methods  many  advantages  of  the 
method  of  incubation  at  370  C.  are  evident,  including  the  ease  of 
maintaining  this  temperature  in  any  laboratory,  the  evident  uni- 
formity of  counts  so  obtained  in  dfferent  places  as  compared  with 
those  obtained  by  the  varying  methods  of  technique,  as  to  temper- 
ature and  incubation  period,  where  room  temperature  is  employed, 
and  the  quickness  with  which  results  are  obtained,  doing  away  with 
large  accumulations  of  uncounted  plates. 

Forty-eight  hour  plates  grown  at  370  C.  give  a  slightly  higher 
count,  not  enough  higher  to  materially  change  the  report,  while 
the  loss  by  "  spreaders  "  is  increased  and  the  count  delayed. 


*  The  lines  of  highest  efficiency  on  a  working  basis  would  seem  to  rest  on  a  48  hour 
incubation  at  370  C.  and  a  5  day  incubation  at  21°  C.  It  would  seem  advisable  to  recog- 
nize as  standard  both  of  these  methods  of  incubation.  (Extract  from  1908  Report  o£ 
American  Public  Health  Association.) 


26o 


CLEAN  MILK 


To  secure  saturation  of  the  atmosphere  the  incubator  should 
be  made  with  a  shallow  depression  over  the  whole  bottom  surface, 
which  may  be  kept  filled  with  water,  or  in  default  of  this  a  large 
shallow  pan  of  water  may  be  kept  on  one  of  the  lower  shelves. 


COUNTING. 

Expression  of  Result. — Since  minor  differences  in  milk  counts 
are  within  the  working  error  of  the  methods  and  are  of  no  signifi- 
cance in  practice,  the  following  scale  has  been  adopted  for  recording 
results  of  market  milk  examinations : 

Counts  below  100,000  are  distinguished  by  ten  thousands. 

Counts  between  100,000  and  500,000  are  distinguished  by  fifty 
thousands. 

Counts  between  500,000  and  1,000,000  are  distinguished  by* 
hundred  thousands. 

Counts  between  1,000,000  and  2,000,000  are  distinguished  by 
two  hundred  thousands. 

Counts  between  2,000,000  and  5,000,000  are  distinguished  by 
iive  hundred  thousands. 

Counts  above  5,000,000  are  distinguished  by  millions. 

Therefore  only  the  following  figures  are  used  in  reporting : 


Below 

IO.OOO 

Above  250,000 

Above  1,400,000 

Above 

10,000 

"    300,000 

'    1,600,000 

u 

20,000 

350,000 

'    1,800,000 

(« 

30,000 

400,000 

1   2,000,000 

" 

40,000 

450,000 

1   2,500,000 

" 

50,000 

"    500,000 

'   3,000,000 

.1 

60,000 

"    600,000 

1   3,500,000 

tt 

70,000 

700,000 

'   4,000,000 

" 

80,000 

"    800.000 

'   4,500,000 

" 

90,000 

"    900,000 

1   5,000,000 

«< 

100,000 

"   1,000,000 

1   6,000,000 

(« 

150,000 

"   1,200,000 

etc.,  by  millions. 

M 

200,000 

Pig.  65. 


Petri  dish  containing  1  cubic  centimeter  of  a  mixture  of  milk(i  c.c.)  diluted 
with  499  c.c.  of  sterilized  water  and  mixed  with  sterilized  agar  culture  medium. 
The  white  spots  in  the  plate  are  colonies  or  collections  of  germs. 

Each  colony  is  supposed  to  represent  a  single  germ  at  the  time  the  milk 
was  examined.  The  dish  rests  on  a  glass  plate  lined  in  white  with  a  black 
background  to  facilitate  counting  the  colonies.  When  the  colonies  are  small 
and  numerous,  only  those  in  every  other  sector  of  the  circle  need  be  counted 
and  the  result  multiplied  by  two.  In  the  above  plate  there  are  only  about  80 
plainly  visible,  but  with  a  common  magnifying  glass — and  one  is  generally  used 
for  counting — about  125  colonies  may  be  seen. 


QUANTITATIVE  BACTERIAL  ANALYSIS         26t 

Counts  on  "  certified  "  or  "  inspected  "  milk  shall  be  expressed 
:as  closely  as  the  dilution  factor  will  allow. 

The  whole  number  of  colonies  on  the  plate  shall  be  counted* 
the  practice  of  counting  a  fractional  part  being  resorted  to  only  in 
.case  of  necessity,  such  as  partial  spreading. 


Fig.  66. 


Counting-Box, 


Various  counting  devices  have  been  recommended  by  differ- 
ent workers.  The  more  simple  ones,  where  the  whole  plate  can 
be  seen  at  once,  are  more  desirable  on  account  of  there  being  less 
likelihood  of  recounting  colonies.  Colonies  too  small  to  be  seen 
with  the  naked  eye  or  with  slight  magnification  shall  not  be 
considered  in  the  count. 


CHAPTER  XII 


MEDIA  MAKING  AND   APPARATUS   REQUIRED  FOR 
BACTERIAL  ANALYSIS  OF  MILK 


METHODS  FOR  MAKING  MEDIA. 

THE  Committee  on  Standard  Methods  of  Bacterial  Milk 
Analysis  of  the  American  Public  Health  Association,  Lab- 
oratory Section,  have  recommended  that  methods  of  the 
Committee  on  Standard  Methods  of  Bacterial  and 
Chemical  Water  Analysis  of  the  American  Public  Health  Associa- 
tion, Laboratory  Section  (with  two  modifications  only,  noted  be- 
low), be  adopted  for  official  work  in  counting-  bacteria  in  milk;  the 
object  being  to  secure  uniformity  of  results  in  all  laboratories  de- 
voted to  this  task.  These  methods  are  by  no  means  to  supersede  any- 
found  valuable  by  individual  investigations  for  particular  purposes, 
but  are  urged  for  adoption  for  official  counts  of  certified,  inspected 
or  market  milk,  and  for  such  investigations  as  relate  directly  to  com- 
parative counts  of  different  classes  of  milks,  at  different  ages,  etc. 
Recently  (Dec.  31,  1907),  they  have  been  recommended  also  by  the 
Committee  on  Methods  of  Identification  of  Bacterial  Species,  of  the 
Society  of  American  Bacteriologists,  for  species  work.  These 
methods  so  far  agreed  upon  are  given  in  the  following  pages. 

NUMERICAL  DETERMINATION   OF  BACTERIA   IN   MILK. 

(From  preliminary  report  of  the  Committee  on  Standard  methods 
of  Bacterial  Milk  Analysis.)  * 

There  is  no  method  known  by  which  the  exact  number  of 
bacteria  in  a  sample  of  milk  may  be  determined,  and  even  when 


*  Published  in  full  in  "  American  Journal  of  Public  Hygiene,"  November,  1907. 

262 


MEDIA  MAKING  AND  APPARATUS  263 

the  best  methods  are  used,  the  count  is  always  less  than  the  actual 
number  of  bacteria  present,  for  the  following  reasons : 

(a)  Many  bacteria  in  process  of  multiplication  are  held  to- 
gether by  adhesive  membranes  in  pairs,  chains  or  masses.  It  is  for 
the  purpose  of  separating  bacteria  thus  joined,  as  well  as  to  obtain 
an  even  mixture,  that  the  sample  itself  and  the  diluted  sample  when 
plating  are  shaken.  This  shaking,  while  it  breaks  up  larger  masses 
and  shortens  long  chains,  does  not  to  any  great  extent  break  apart 
the  shorter  chains,  diplococci,  etc.  Each  of  these  groups  of  bacteria, 
when  caught  in  the  solid  medium,  develops  as  a  single  colony. 

(b)  It  is  impossible  to  obtain  a  medium  suited  to  the  food 
requirements  of  all  species  or  races  of  bacteria.  It  has  been  found 
by  experiment  that  a  medium  consisting  chiefly  of  a  watery  extract 
of  raw  meat  and  peptone,  alkaline  to  litmus  and  slightly  acid  to 
phenolphthalein,  will  furnish  the  best  food  for  the  greatest  number. 

(c)  These  varying  forms  of  minute  vegetable  life  require 
varying  temperatures  for  their  best  development.  Many  forms 
which  will  develop  at  room  temperature  will  not  grow  at  body 
temperature.  Some  require  a  very  high  temperature  for  their  best 
growth. 

(d)  Some  bacteria  develop  in  an  atmosphere  free  from  oxy- 
gen, some  only  where  oxygen  is  present ;  many  are  facultative,  i.  c, 
growing  under  either  condition.  Bacteria  which  require  an  oxygen- 
free  atmosphere  do  not  develop  in  plates  as  generally  prepared. 
Bacteria  requiring  oxygen,  if  deep  in  the  medium,  develop  but 
slowly,  as  they  then  obtain  free  oxygen  only  by  diffusion. 

(c)  Many  forms  are  slow  in  developing  into  visible  colonies, 
some  requiring  three  or  four  days.  On  the  other  hand,  in  plates 
grown  for  several  days,  many  small  colonies  are  obscured  in  the 
growth  of  larger  ones. 

(/)  Each  bacterium  requires  a  certain  amount  of  nourish- 
ment for  development.  There  are  also  antagonistic  forms  which 
will  not  develop  in  close  proximity  to  each  other.     It  therefore 


264  CLEAN  MILK 

follows  that  in  a  crowded  plate,  i.  c,  over  two  hundred  colonies, 
many  of  the  weaker  forms  will  not  develop.  This  is  easily  proven: 
by  making  a  higher  dilution.     (See  p.  254.) 

(g)  Spreaders  *  and  molds,  by  their  rapid  surface  growth, 
merge  with  other  surface  colonies  and  obscure  deeper  ones. 

(/?)  Samples  kept  in  the  collecting  case  at  340  F.  for  vary- 
ing periods  have  shown  a  tendency  to  decrease  in  the  number  of 
bacteria  which  will  develop  into  colonies.  Samples  kept  in  dilution 
water  for  several  hours  have  shown  a  marked  decrease  in  the 
number  of  bacteria  which  will  develop  into  colonies. 

On  account  of  these  reasons  strict  adherence  to  standard  pro- 
cedure is  of  especial  importance,  since  there  are  so  many  points 
where  disagreement  may  result  if  uniform  technique  is  not  fol- 
lowed.    (See  p.  241.) 

SCHEDULE  FOR  MAKING  THE  PRINCIPAL  ARTIFICIAL  MEDIA. 

(Arranged  by  H.  W.   Hill  in  accordance  with  recommendations 
of  the  committee  on  standard  methods:  A.  P.  H.  A.) 

Plain  nutrient  agar ;  plain  nutrient  gelatin ;  plain  nutrient  broth ; 
and  their  modifications  (i.  c,  glycerine  agar,  plain  dextrose  agar, 
muscle-sugar-free  dextrose  (lactose,  maltose,  etc.)  agar;  muscle 
-sugar-free  dextrose  (maltose,  etc.)  litmus  agar;  glycerine  broth; 
plain  dextrose  broth ;  sugar-free  broth ;  muscle-sugar-free  dex- 
trose (maltose,  etc.)  broth;  muscle-sugar-free  dextrose  (maltose, 
etc.)  litmus  broth,  and  other  similar  combinations,  may  all  be  made 
by  these  methods. 


*  "  Spreaders  "  are,  properly,  intensely  vigorous  and  motile  bacteria;  these  tend  to 
travel  over  the  surface  of  the  agar,  instead  of  remaining  within  the  bounds  of  a  def- 
inite colony.  But  any  surface  colony  may  be  spread  over  the  surface  of  a  plate,  if 
water,  separated  from  the  medium,  condenses  on  the  agar,  or  drops  down  from  conden- 
sation on  the  cover  of  the  Petri  dish.  The  use  of  earthenware  (or"  porous  ")  tops  for 
Petri  dishes,  in  place  of  glass,  excludes  very  largely  spreading  from  this  cause,  reducing 
the  total  of  plates  spoiled  by  spreading  from  nearly  40^  to  less  than  ■$%. 


MEDIA  MAKING  AND  APPARATUS  26s 

STEPS   COMMON   TO   ALL  VARIETIES. 

1.  Infuse  finely  chopped  lean  round  steak  (beef)  free  from 
fat,  gristle,  bone,  etc.,  in  cold  water — proportions  1  gram  muscular 
tissue  to  1  c.c.  (or  gram)  of  distilled  water;  weigh  container  and 
contents;  leave  covered  in  ice-chest  for  24  hours.  (Example:  1000 
grams  meat  with  1000  grains  (or  c.c.)  water). 

2.  Weigh  container  and  contents,  adding  water  to  make  up 
any  loss  by  evaporation ;  (i.  e.,  the  meat  plus  the  water  should  weigh 
2000  grams)  ;  filter  through  canton  flannel,  squeezing  the  successive 
small  portions  of  the  meat  left  on  filter;  the  filtrate  should  weigh  (or 
measure)  the  same  amount  as  the  water  added  in  No.  1.  If  less, 
squeeze  the  meat  more  thoroughly;  if  more,  reject  the  surplus. 

3.  Add  to  the  filtrate  (known  as  "  1  to  1  meat  infusion") 
2%  by  weight  of  dried  commercial  "peptone"  (Witte's),  i.  e.p 
20  grams.  (Note:  Commercial  "peptones"  are  really  largely 
albumose.) 

4.  Heat  over  water  bath  until  peptone  is  dissolved.  The  "  1 
to  1  meat  infusion  plus  peptone  "  should  not  be  allowed  to  rise 
above  500  C.  during  this  process ;  restore  loss  by  evaporation,  i.  e., 
by  weighing  and  restoring  to  original  weight  (1000  grams)  by 
addition  of  water. 

STEPS   WHICH   DIFFERENTIATE   THE  DIFFERENT    MEDIA    FROM    EACH 

OTHER. 

5.  (a)  Plain  nutrient  broth :  Add  to  "  1  to  1  meat  infusion  -f- 
peptone  "  (say  1,000  grams  or  c.c.)  an  equal  quantity  of  water,  *.  e., 
to  make  2,000  grams  or  c.c.  For  glycerine  broth,  add  also  glycer- 
ine by  volume  to  make  5%  of  the  total  mixture  (i.  c,  100  c.c.)  ;  for 
plain  dextrose  (or  maltose,  lactose,  etc.)  broth,  add  similarly  dex- 
trose (or  maltose,  lactose,  etc.)  to  make  1%  by  weight  of  the  total 
mixture  (i.  e.,  20  grams). 


266  CLEAN  MILK 

(b)  Plain  nutrient  agar:  Add  to  "  i  to  i  meat  infusion  -f- 
peptone  "  (i.  e.,  1,000  grams  or  c.c.)  an  equal  quantity  of  "agar 
jelly"  (z.  e.,  1,000  grams),  hot  or  cold,  prepared  by  dissolving 
thread  agar  (30  grams)  in  water  (to  make  1,000  c.c.)  by  boiling  to 
make  a  3%  solution  (for  milk  work,  2%),  which  jellies  on  cooling. 
For  glycerine  agar,  plain  dextrose,  etc.,  agar,  add  constituents  as 
under  broth.  (Note:  Plain  nutrient  agar,  made  as  here  directed, 
except  that  the  percentage  of  agar  in  the  finished  medium  is  1  % 
instead  of  Ij4%,  and  the  reaction  1.5%  acid  instead  of  1%  acid,  is 
the  official  count  medium  recommended  by  the  Committee  on 
Standard  Methods  of  Bacterial  Milk  Analysis.) 

(c)  Plain  nutrient  gelatin:  Add  to  "  1  to  1  meat  infusion  -f- 
peptone  "  (i.  e.,  1,000  grams  or  c.c.)  an  equal  quantity  of  "  gelatin 
jelly,"  hot  or  cold  (prepared  by  dissolving  sheet  gelatin  200  grams 
in  water  (to  make  1,000  c.c),  heated  not  above  400  C,  to  make  a 
20%  solution,  which  jellies  on  cooling.  For  glycerine  gelatin  and 
plain  dextrose,  etc.,  gelatin,  add  constituents  as  under  broth. 

(d)  For  all  media  which  should  be  muscle-sugar-free  (either 
for  use  as  strictly  sugar-free  media,  i.  c,  as  indol  broth,  or  to  get 
rid  of  all  muscle  sugar  first,  in  order  to  add  exact  quantities  of  other 
sugars,  adjust  the  "  1  to  1  meat  infusion+peptone  "  to  the  1.5% 
(normal)  acid  point,  as  indicated  below,  warm  to  370  C.  and  in- 
oculate with  a  vigorous  24  hours  culture  of  B.  coll  in  plain  broth. 
Set  in  incubator  at  2,7°  C.  for  12  hours  (i.  e.,  over  night).  In  this 
time  all  the  sugar  should  be  disintegrated  by  the  bacillus.  Restore 
any  loss  by  evaporation.  Then  proceed  as  under  plain  nutrient 
broth,  etc.,  according  to  the  medium  desired.  (Note:  Litmus  solu- 
tion, as  described  below,  or  azolitmin,*  2%  solution,  1%  of  the  total 
mixture,  may  be  added  to  any  medium,  as  desired,  at  Step  5.) 

Note  :  A  test  for  the  presence  of  sugar  may  be  made  as  follows : 
— Fill  a  fermentation  tube  with  the  medium  to  be  tested   (after 


'  This  may  be  bought  of  makers  of  biological  products. 


MEDIA  MAKING  AND  APPARATUS  26^ 

neutralizing  it).  Autoclave:  when  cool,  inoculate  with  a  pure 
culture  of  B.  coli  and  incubate  24  hours  at  370  C.  If  gas  collects 
in  the  closed  arm  as  the  result  of  growth,  a  considerable  quantity  of 
sugar  is  still  present.  If  no  gas  collects,  but  a  growth  occurs  in 
the  closed  arm,  a  trace  of  sugar  is  still  present.  If  the  closed  arm 
remains  free  of  growth,  all  the  sugar  has  been  removed. 

FURTHER  STEPS  COMMON  TO  ALL  MEDIA, 

6.  Adjust  to  the  phenolphthalein  1.5%  (normal)  acid  point 
(except  that  broths  containing  added  sugars  should  be  adjusted  to 
the  phenolphthalein  neutral  point).     See  below. 

7.  Heat  over  boiling  water  for  30  minutes  (i.  e.,  the  medium 
itself  should  be  at  or  about  ioo°  C.  for  just  30  minutes). 

8.  Restore  loss  by  evaporation  to  double  original  weight  of 
filtrate  (Step  2;  i.  c,  to  2,000  grams)  ;  check  and,  if  necessary,  ad- 
just reaction. 

9.  Boil  over  a  free  flame  for  just  five  minutes :  counting  the 
five  minutes  from  the  beginning  of  actual  boiling.  Stir  constantly 
to  prevent  burning,  especially  in  making  nutrient  gelatin  of  any 
variety. 

10.  Restore  loss  by  evaporation;  check  and  adjust  reaction. 

11.  Filter,  tube,  and  sterilize. 

Note :  In  all  cases,  the  weight  of  the  medium  before  filtering, 
i.  e.,  at  the  completion  of  Step  10,  should  be  double  the  weight  of  the 
filtrate  obtained  in  Step  2. 

Note :  About  5  c.c.  of  agar,  gelatin  or  liquid  media  should 
be  placed  in  each  test  tube,  except  that  for  all  media  to  be  used  in 
plating,  10  c.c.'s  (exactly)  should  be  used. 

Note :  The  Committee  recommends  alternatively,  the  addition 
of  sugars  and  litmus  just  before  tubing  and  sterilization  in  Step  11, 
instead  of  in  Step  5  as  above. 


268 


CLEAN  MILK 


Note :  All  media  should  be  kept  for  use  in  a  dark,  cool,  dust- 
free  place,  i.  e.,  a  refrigerator  or  ice-chest. 


Fig.  67. 


Filling  test  tubes  with  a  measured  amount  of  culture  medium. 
(After  Conn.) 

Note :  These  methods  are  those  of  the  Committee  on  Standard 
Methods  of  Water  Analysis  of  the  American  Public  Health  As- 
sociation, except  as  follows: 


MEDIA  MAKING  AND  APPARATUS  26^ 

1st.  They  include  several  media  not  mentioned  in  the  schedule 
of  the  Committee. 

2nd.  For  making  gelatin,  the  water  is  added  with  the  sheet 
gelatin  at  Step  5  (c)  above,  instead  of  adding  the  water  at  Step  1 
and  the  sheet  gelatin  at  Step  5,  as  in  the  Committee  schedule. 

3rd.  In  Step  4,  the  Committee  specifies  6o°  C.  as  the  limit  for 
temperature  in  dissolving  peptone. 

4th.  The  operations  are  described  in  somewhat  greater  detail. 
None  of  these  four  changes  are  of  moment  except  as  contributing  to 
simplicity  and  uniformity  of  technique. 

'5th.  The  adjustment  of  reaction  is  made  to  precede,  instead 
of,  as  in  the  Committee  schedule,  follow,  the  30  minutes  heating 
on  the  water  bath. 

6th.  The  period  of  boiling  over  free  flame  is  given  as  5 
minutes  instead  of  the  2  minutes  in  the  Committee  schedule. 

The  changes  5  and  6  were  suggested  to  the  Committee  and 
accepted  by  them  for  reasons  given  in  the  writer's  article  (Journ. 
Infec.  Diseases,  Supplement  II,  p.  223),  but  since  no  revision  of  the 
report  has  since  been  made,  the  schedule  appears  uncorrected  in 
existing  reports. 

Milk  Medium. — Plain,  fresh,  rich  milk  (preferably  "certi- 
fied "),  skimmed  by  centrifugalization,  of  a  reaction  not  over  1.5% 
(normal)  acid,  is  to  be  brought  to  1%  (normal)  acid,  tubed  and 
sterilized. 

Litmus  milk  is  prepared  by  adding  to  the  above,  before  tubing, 
1%  of  the  litmus  solution  described  below  (or  of  a  2%  aqueous 
azolitmin  solution,  when  this  can  be  procured  of  the  proper  grade.) 

Artificial  Milk. —  (Lactose  Nutrose  Solution). — Owing  to  the 
fact  that  milk  has  a  varying  acidity  and  to  the  inconvenience  of 
securing  separator  milk,  which,  when  secured,  is  not  wholly  free 
from  fat,  the  following  is  offered  as  a  substitute:  Nutrose  (Sodium 
— phosphate — casein),  2.6  grams;  lactose,  1.1  grams;  water  (dis- 
tilled), 100  c.c.    Heat  slightly  to  dissolve  the  nutrose.    Do  not  boil. 


270  CLEAN  MILK 

After  heating  for  about  15  minutes,  filter  through  cotton,  tube  and 
autoclave  at  15  lbs.  for  15  minutes. 

(This  substitute  was  suggested  by  H.  W.  Hill  in  1898,  worked 
out  by  A.  J.  Chesley,  and  adopted  in  the  Minnesota  State  Board  of 
Health  Laboratories,  1908.) 

Potato  Medium. — Good  sized,  plump  potatoes,  free  from  bad 
spots,  are  Well  washed  and  peeled ;  cylinders  of  a  size  to  fit  the  test 
tube  are  cut  from  them  with  a  cork  borer  of  appropriate  size  to 
slip  into  the  test  tubes ;  the  cylinders  are  cut  diagonally  across  and 
the  resulting  half-cylinders  washed  over  night  in  running  water; 
they  are  then  dropped,  large  end  down,  one  half-cylinder  to  a  tube, 
into  test  tubes  containing  wads  of  cotton,  saturated  with  water, 
pushed  to  the  bottom  of  the  tube,  the  potato  resting  on  the  wet 
cotton ;  the  tubes  are  then  plugged  and  sterilized.  Note :  Potato 
remaining  sharply  acid  to  litmus  paper  after  the  over-night  wash- 
ing, should  be  rejected. 

Nitrate  Broth. — Dissolve  1  gram  peptone  in  one  litre  of  water; 
add  2  grams  nitrite-free  potassium  nitrate;  adjust  to  \°/c  (normal) 
acid  to  phenolphthalein,  tube  and  sterilize. 

Lofflcr's  Blood  Serum. — To  glycerine  dextrose  broth  3  parts, 
add  1  part  fresh  serum  (obtained  by  collecting  cow,  pig,  horse,  etc., 
blood  in  a  clean  pail  and  allowing  it  to  stand  in  cold  storage  for 
24  hours ;  the  blood  clots,  the  clot  shrinks,  and  with  care,  the  straw- 
colored  serum  or  liquid  part  may  be  drawn  off  with  a  syphon  or 
large  pipette).  Adjust  reaction  to  0.8%  acid,  and  coagulate  thus: 
slope  tubes  to  get  a  large  surface,  being  careful  not  to  wet  plugs, 
in  an  autoclave,  which  does  not  leak  steam  at  all.  Run  up  slozcly 
to  ioo°  C,  taking  great  care  that  all  the  air  is  driven  out  by  the 
steam.  After  maintaining  the  temperature  at  ioo°  C.  for  20 
minutes,  close  outlet  cock  and  run  up  slowly  to  15  lbs.  pressure, 
still  preventing  even  momentary  escape  of  steam  even  from  one 
safety  valve.  Hold  at  15  lbs.  for  15  minutes,  then  cut  off  steam 
or  gas  supply  and  cool  to  room  temperature  before  opening.    Open. 


MEDIA  MAKING  AND  APPARATUS  271 

pet  cock  first  a  little  at  a  time,  until  pressure  inside  and  out  is 
equal.  This  process,  should  not  take  more  than  one  to  one  and 
one-half  hours. 

The  general  principal  of  the  above  was  devised  in  the  Minn. 
State  Board  of  Health  Laboratories,  but  is  applied  there  to  chloro- 
formed serum,  and  requires  about  four  times  as  long.  As  given, 
the  method  was  devised  in  the  Boston  Board  of  Health  Bacteriolog- 
ical Laboratory,  and  is  for  fresh  serum  only. 

Test  for  Indol. — Grow  the  bacteria  which  it  is  desired  to  test 
for  10  days  in  muscle-sugar-free  broth  ("indol  broth").  Add  10 
drops  of  sulphuric  acid  and  1  c.c.  of  an  aqueous  solution  of  sodium 
nitrite  ( 1  in  10,000)  ;  a  pink  color  developing  at  once  or  within  half 
an  hour,  especially  on  warming  gently  to  500  C,  indicates  presence 
of  indol.  Certain  bacteria  produce  nitrites.  If  such  produce  indol 
also  (as  in  the  case  of  the  cholera  spirillum  (microspira  comma), 
sulphuric  acid,  added  as  described,  produces  the  color  without 
further  addition  of  nitrite.     This  is  called  the  cholera  red  reaction. 

Test  for  Formation  of  Nitrites  from  Nitrates. — Grow  the 
bacteria  for  5  days  in  "  nitrate  broth."  Add  to  the  culture  2  c.c. 
of  freshly  made  mixture  of  the  following  solutions:  (a)  naphyla- 
mine,  1%  aqueous  solution;  (b)  sulphanilic  acid,  3%  solution  in 
dilute  acetic  acid.  A  pink  color  shows  presence  of  nitrite.  Nitrite 
is  absorbed  from  the  air,  and  in  laboratory  air  much  nitrite  is 
usually  present;  hence  care  should  be  taken  at  every  stage  to  avoid 
air-exposure  so  far  as  possible,  and  uninoculated  tubes  of  the  ni- 
trate medium,  exposed  to  the  same  conditions  as  those  inoculated, 
should  be  tested  at  the  same  time  as  a  control. 

Litmus  Solution. — Take  200  to  500  grams  of  litmus  cubes 
(chalk  saturated  in  crude  litmus  and  dried).  Pulverize  in  mortar; 
wash  all  blue  out  of  chalk  with  water  on  a  filter  paper.  Evaporate 
water  to  dryness.  Pulverize  residue  and  wash  on  filter  with  al- 
cohol (9570  to  extract  the  red  portion.  When  the  alcohol  pass- 
ing through  the  litmus  comes  away  colorless  (8  or  9  litres  of  al- 


272  CLEAN  MILK 

cohol  are  often  required),  dry  residue,  weigh  and  dissolve  in  water 
in  proportions  to  make  a  s^o  solution.  Add  1/5  of  ic/o  chloroform 
to  the  solution  to  preserve  it.  Of  this  solution,  10  to  15  c.c.  per 
litre  of  media  should  give  a  good  blue  tint.  Note :  On  autoclaving, 
most  litmus  media  lose  color  entirely.  The  color  returns  on  cooling 
and  exposure  to  air.     (Method  of  Minn.  State  Board  of  Health 

Laboratories). 

Cohn's  Solution. 
Distilled  water,  containing  (  Per  cent. 

Tribasic  calcium  phosphate 0.05 

Magnesium  sulphate 0.50 

Acid  potassium  phosphate   0.50 

Ammonium  tartrate 1.00 

Sterilize  by  intermittent  method  in  free  steam. 

Uschinsky's  Solution. 

Distilled  water  containing  Per  cent. 

Calcium  chloride 01 

Magnesium  sulphate 02 

Acid  potassium  phosphate to 

Sodium  chloride 50 

Ammonium  lactate 1  .oo 

Asparagin 34 

Glycerine 4-°o 

Sterilize  by  intermittent  method  of  free  steam. 

Silicate  Jelly. 

Solution  (a)  distilled  water,  containing —  Per  cent. 

Calcium  chloride 02 

Magnesium  sulphate 10 

Ammonium  sulphate So 

Solution  (b)  distilled  water,  containing — 

Potassium  phosphate 2 

Sodium  carbonate 1.2 

Solution  (c)  distilled  water,  containing  3.4^  silicic  acid. 

Pour  about  5-10  c.c.  of  (c)  into  a  Petri  dish  :  add,  with  stirring,  a  mixture  of  equal' 
parts  of  (a)  and  (b).  Sterilize  intermittently  in  free  steam;  streak  upon  the  jelly  thus 
prepared  the  organisms  it  is  desired  to  grow. 

USES     OF     MEDIA. 

The  chief  media  in  ordinary  use  are  valuable  because  each 
elicits  certain  characteristics  of  bacteria  which,  taken  together,  per- 
mit the  recognition  of  the  identity  of  the  bacteria.    The  methods  of 


MEDIA  MAKING  AND  APPARATUS  273 

preparing  media  generally  accepted  are  given  on  p.  263.     The  chief 
uses  to  which  they  are  put  are  described  below. 


Plain  nutrient  agar — remains  solid  at  370  C. — 400  C. ;  melts  at 
ioo°  C:  solidifies  again  about  40 °  C.  Used  for  plating  (in 
10  c.c.  quantities)  and  for  characteristics  of  growth  (in 
5  c.c.  quantities;  tubes  are  slanted  while  cooling  to  secure  a 
wide  long  surface  of  jelly).  The  sizes,  shapes  and  staining  of 
bacteria  after  growth  on  this  medium  for  24  hours  are  taken 
as  the  standards  in  describing  their  morphology.  Chromogenic 
and  fluorescent  bacteria  show  their  pigments  well  on  this, 
medium.  For  plates  to  be  incubated  at  2,7°  C.  porous  tops, 
should  be  used,  to  lessen  "  spreading." 

Fig.  68. 


Hardening  Agar  Slants.     (After  Conn.) 

Plain  nutrient  gelatin — if  well  made,  remains  solid  at  240 — 250  C. ; 
melts  just  above  this  point ;  solidifies  on  cooling  to  240 — 25 °  C. 
Used  for  plating  (in  10  c.c.  quantities)  and  for  characteristics 
of  growth  (in  5  c.c.  quantities;  tubes  are  vertical  while  cooling, 
and  inoculations  are  made  by  thrusting  a  straight  needle — not 
'  a  looped  needle — half  way  to  the  bottom  of  the  jelly  along  the 
central  axis  of  the  tube — thus  making  a  "stab").  Aiany 
bacteria  liquefy  gelatin,  through  the  action  of  a  soluble  di- 
gestive ferment  (or  enzyme)  secreted  by  them;  many  do  not 
liquefy  it,  hence  a  point  of  distinction  between  species  is 
yielded;  the  shape,  size  and  rapidity  of  development  of  the 


274  CLEAN  MILK 

liquefaction  further  assists  in  recognition.  Plates,  to  remain 
solid,  must  be  incubated  at  about  22°  C.  The  great  objections 
to  gelatin  for  plates  are  the  difficulty  of  maintaining  the  tem- 
perature at  22°  C,  and  the  liquefaction  due  to  some  species, 
which  usually  quickly  destroys  the  chief  value  of  a  plating 
medium — its  solidity. 

Modifications  of  agar  and  gelatin  media — the  sugars  are  added 
chiefly  to  elicit  gas  formation  (best  tested  in  stabs)  ;  litmus 
to  indicate  changes  in  reaction ;  glycerine,  because  certain 
bacteria  are  believed  to  grow  better  in  its  presence ;  milk  for  a 
similar  reason. 

Plain  nutrient  broth — used  chiefly  for  characteristics  of  growth  on 
liquids  and  to  elicit  the  typical  arrangements  of  cells  when 
growing  freely  (i.  e.,  chains,  clusters,  etc.)  ;  also  for  motility, 
which  develops  better  in  liquids  than  on  solids.  Tube  5  c.c.  in  a 
test  tube;  in  fermentation  tubes,  use  enough  to  half  fill  bulb 
and  completely  fill  closed  arm.  The  modifications  (with 
sugars,  litmus,  glycerine,  etc.)  are  made  for  the  reasons  given 
under  agar  and  gelatin.  Gas  formation  is  best  determined 
quantitatively  and  qualitatively,  by  the  use  of  sugar  broths  in 
fermentation  tubes. 

Potato — for  gross  characteristics  of  growth. 

Milk — for  the  detection  of  coagulation  of  milk,  the  subsequent  so- 
lution of  the  clot,  and  other  evidences  of  digestive  action. 
Milk  is  too  full  of  casein  particles,  fat  and  albumin  to  yield 
good  smear  preparations  for  morphological  study  as  a  rule. 
Combined  with  litmus,  acid  or  alkali  formation  can  be  de- 
termined, and  changes  in  reaction  noted.  Litmus  milk  often 
becomes  decolorized  by  bacterial  absorption  of  the  oxygen 
necessary  to  its  coloration. 


MEDIA  MAKING  AND  APPARATUS  275 

Scrum — apart  from  characteristics  of  growth  and  morphology, 
serum  becomes  translucent  and  later  liquified  under  the  action 
of  certain  bacteria.  The  morphology  of  bacteria  growing  on 
this  medium  is  readily  determined  also,  and  is  sometimes 
characteristic. 

Starch  jelly — chiefly  used  for  appreciation  of  diastatic  action. 

Silicate  jelly  :  Cohn's  and  Uschinky's  solutions — are  chiefly  used  in 
the  study  of  certain  bacteria  which  grow  best  or  exclusively  on 
such  media ;  and  in  the  search  for  synthetic  media  applicable  to 
all  bacteria. 

TECHNIQUE  OF   HANGING  DROP. 

Secure  to  a  slide  with  thick  Canada  balsam,  softened  by  heat, 
a  ring  of  glass,  celluloid,  rubber,  metal,  etc.,  about  24"  diameter, 
1/16"  wide,  1/8"  thick.  Vaseline  the  free  edge  of  the  ring.  Mix 
on  a  coverslip  one  drop  of  sterile  water  with  one  drop  of  the 
material  to  be  examined,  as  directed  for  staining,  but  instead  of 
drying,  turn  the  coverslip  down  over  the  ring,  so  that  it  sticks  to 
the  vaselined  edge  with  the  drop  downward  within  the  ring.  Focus- 
ing carefully  on  the  drop  from  above,  the  bacteria,  etc.,  in  the  drop 
will  be  seen. 

TECHNIQUE   OF    SIMPLE    STAIN. 

Place  on  a  clean  slide  with  an  inoculating  needle  one  drop 
of  sterile  water.  Mix  with  this  one  drop  of  a  broth  culture,  of 
milk,  of  water  or  other  liquid  containing  bacteria;  dry  over  a  flame 
gently  (without  boiling),  spreading  with  the  needle  from  time  to 
time  to  secure  a  smooth,  even  "  smear."  When  dry,  and  still  hot, 
place  two  or  three  drops  of  95%  alcohol  on  the  smear  and  allow 
it  to  dry.  This  alcohol  treatment  may  be  omitted  in  the  case  of 
milk,  and  should  be  omitted  when  the  material  to  be  examined  is 
from  a  culture  on  solid  media  (agar,  gelatin,  potato,  etc.) 


276  CLEAN  MILK 

Stain  with  aqueous  fuchsin,  aqueous  methylene  blue,  Loffler's 
methylene  blue  or  other  simple  stains  (i.  e.,  not  combined  with  a 
mordant),  thus:  flood  the  smear  with  the  dye,  wash  off  in  water 
thoroughly,  and  dry.  Simple  ("  aqueous  ")  stains  consist  of  the  dry 
stain  or  dye,  I  part,  alcohol  10  parts,  water  ioo  parts. 

Note:  Young  cultures  stain  well  with  methylene  blue,  and  pe- 
culiarities of  staining  are  best  shown  with  this  stain,  such  as  polar 
granules,  vacuoles,  metachromatic  granules,  etc.  The  intensity  with 
which  this  stain  colors  the  bacteria  is  important,  certain  species  stain- 
ing faintly,  others  deeply. 

In  old  cultures,  methylene  blue  stains  only  the  more  vigorous 
survivors:  those  which  have  died  (as  a  result  of  auto-intoxication, 
etc.,  not  those  killed  artificially  by  heat)  losing  the  power  to  stain 
well  with  this  dye;  with  aqueous  fuchsin,  the  tendency  with  young 
cultures  is  to  overstain;  with  old  cultures,  the  degenerate  forms 
stain,  as  well  as  those  not  degenerate. 

TECHNIQUE  OF  ZIEHL-NIELSEN   STAIN    FOR  TUBERCLE   BACILLI    AND 

SPORES. 

For  tubercle  bacilli:  Prepare  a  smear  of  the  suspected  material; 
cover  the  smear  with  an  excess  of  the  Ziehl-Nielsen  stain ;  heat 
five  minutes,  without  boiling,  however.  Wash  in  water ;  decol- 
orize until  a  faint  pink  only  remains  with  acid  alcohol  (HO 
5  parts,  alcohol  ioo  parts.)  Wash  and  counter-stain  with 
methylene  blue.  Wash  and  mount.  The  tubercle  bacilli  are 
seen  red  in  a  blue  field.  Since  bacilli  not  unlike  the  tubercle 
bacillus  in  appearance,  and  staining  by  the  same  method,  are 
found  at  times  on  certain  grasses,  hay,  etc.,  and  in  butter,  etc., 
conclusive  proof  that  tubercle  bacilli  are  present  in  a  given 
farm  product  cannot  be  had  from  the  staining  reaction  alone, 
but  requires  confirmation  from  careful  study  of  the  effects  upon 
a  guinea-pig  of  inoculation  with  the  bacterium  in  question. 


MEDIA  MAKING  AND  APPARATUS  277 

.For  spores. — Proceed  as  above,  but  in  decolorizing  use  alcohol  r 
part,  in  water  3  parts,  instead  of  acid  alcohol. 

gram's  stain. 

Prepare  a  saturated  solution  of  gentian  violet  in  alcohol  and 
keep  as  a  stock  solution. 

Prepare  fresh  each  time  anilin  oil  water  thus : 

Anilin  oil     1  c.c. 
Water  50  c.c. 

Shake  violently ;  filter  repeatedly  until  clear.  Mix  three  parts 
of  the  anilin  oil  water  with  one  part  of  the  gentian  violet  solution — 
-thus  making  "  anilin-oil-gentian-violet." 

Process. 

1.  Prepare  smears  as  usual. 

2.  Stain  in  anilin-oil-gentian-violet,  iJ/2  minutes. 

3.  Wash  in  water;  smear  now  deep  violet. 

4.  Wash  with  Gram's  solution  (iodin  1,  potassium  iodide  2, 
water  300)  ;  smear  now  purple  black. 

5.  Decolorize  with  successive  small  quantities  of  95%  alcohol 
until  no  more  color  comes  away  in  the  alcohol. 

6.  Counterstain  with  Bismark  brown  (5%  aqueous  solution). 

7.  Wash,  dry  and  mount  for  examination. 

This  rather  important  stain  depends  for  its  differential  value 
on  the  fact  that  whereas  all  species  of  bacteria,  stained  by  anilin- 
oil-gentian-violet,  may  be  decolorized  with  alcohol,  certain  species, 
if  iodin  be  used  to  fix  the  stain,  become  undecolorizable,  while  others 
lose  the  stain  as  readily  after  the  iodin  treatment  as  without  it. 


278  CLEAN  MILK 

EXAMINATIONS   FOR  B.   COLI   IN   MILK. 

This  examination,  like  that  for  pus  and  for  streptococci,  has  not 
yet  had  its  true  value  or  significance  determined.  Its  advocate, 
Stokes,  finds  a  relation  between  the  frequency  with  which  it  is 
found  and  the  number  of  bacteria  present — i.  c,  high  count  milk 
is  much  more  likely  to  yield  colon  bacilli  than  low  count  milk.  It  is 
unlikely  that  this  test  as  a  rule  indicates  more  than  the  admission 
of  manure  to  the  milk  in  unusual  proportions.  Stokes'  method  is 
as  follows: 

Ox  bile  is  collected  from  slaughter  houses;  1%  of  lactose 
added ;  this  medium  is  placed  in  fermentation  tubes  and  sterilized. 
For  the  test,  1/1000  c.c.  of  the  milk  in  question  is  added  and  the 
tube  incubated  at  370  C.  for  J2  hours;  if  more  than  15%  of  the 
length  of  the  closed  arm  of  the  fermentation  tube  is  occupied  by 
gas  at  the  end  of  this  timer  plates  are  made  from  the  fluid,  and 
colonies  isolated  and  tested  as  for  B.  coll. 


LIST   OF    APPARATUS  REQUIRED    FOR  A    SIMPLE    LABORATORY    FOR  BACTERIAL   WORK 
RELATED   TO    MILK. 

Work  table,  of  wood,  firm  and  smooth,  not  painted  or  varnished,  but  oiled  or  vaselined 
(hot)  or  treated  with  aniline  black  mixture;  well  lighted  by  a  north  window:  40 
inches  above  floor  for  "  stand  up  "  work,  30  inches  for  "  sit  down  "  work. 

Water  supply:  Preferably  hot  and  cold,  emptying  into  a  large  sink  (about  3'  x  i'-i'  x  J'); 
a  much  smaller  sink,  and  a  supply  consisting  of  a  barrel  with  faucet,  or  even  a  large 
chamber  pitcher,  may  be  used. 

Waste  pipes  of  ordinary  plumbing  may  be  used:  or  wooden  rain-troughs  (eave  pipes) 
may  be  set  below  the  sink  outlet  and  used  to  conduct  the  waste  to  an  appropriate 
outlet. 

Gas  supply.  Gas-pipes,  fitted  with  simply  keyed  gas  outlets  for  attachment  of  rubber 
hose  for  Bunsen  burners  and  gas  stoves  of  one  and  two  plates  may  be  used ;  or 
alcohol  lamps  of  the  Barthel  type  may  replace  the  Bunsen  burners;  of  the  Glogau 
type,  the  gas  stoves. 

Sterilizers.  A  very  satisfactory  hot-air  oven  for  empty  glassware  of  all  descriptions 
consists  of  an  ordinary  gas  stove  oven, -used  on  a  two-plate  gas  stove  or  on  a  Glogau 
type  alcohol  stove ;  even  the  oven  of  an  ordinary  cook  range  may  be  used. 

Arnold  sterilizers  for  media,  contained  in  flasks,  test  tubes,  etc.,  for  free  steam  ;  these  may 
be  obtained  of  tin  or  of  copper;  or  a  good  home-made  substitute  may  be  constructed 
by  attaching  to  the  lip  of  a  deep  tin  or  agate  four-quart  pan  (to  contain  the  boiling 
water)  a  tin  cylinder  with  vertical  sides,  a  fairly  tight  cover  and  a  perforated  bottom 


MEDIA  MAKING  AND  APPARATUS  279 

the  steam  rising  through  the  latter.  If  possible,  however,  an  autoclave  should  be 
obtained ;  one  type  can  be  heated  directly  by  gas,  making  its  own  steam  ;  the  same 
can  be  obtained,  modified  for  attachment  directly  to  steam  pipes  carrying  steam 
under  pressure.  For  laboratory  purposes  the  Bramhall  Deane  (New  York)  auto- 
clave (2B)  is  highly  to  be  recommended. 

Sterilization  in  the  Arnold  sterilizer  must  be  done  on  three  successive  days  with 
full  steam  for  twenty  minutes  each  day,  the  media  being  kept  at  room  temperature 
in  the  intervals  between  steaming.  With  the  autoclave  a  single  sterilization  at 
fifteen  pounds  pressure  (1200  C.)  is  sufficient. 

Rubber  tubing,  white,  of  a  proper  size  to  fit  snugly  both  gas  outlets  and  Bunsen  burners. 

Funnels,  }  or  i  liter,  agate  ware,  or  copper  tinned  inside,  or  glass. 

Granite  or  agate  ware,  "  double  boiler  "  with  cover,  capacity  of  inside  pan  at  least  four 
liters.     Large  granite  or  agate  ware  spoons. 

Wire  baskets  for  test  tubes,  7"  long,  5"  wide,  5"  deep,  smooth  wrapped  corners  and  edges, 
no  solder. 

Petri  dishes,  with  porous  tops,  4"  diameter,  §"  to  i"  deep. 

Tumblers,  to  be  used  with  cotton  in  bottom  for  holding  test  tubes  ;  or  wire  test  tube 
racks,  Harvard  pattern. 

Funnels,  2",  4", 6"  diameter  for  filtering  stains,  etc. 

Filter  paper — ( Schleicher  &  Schull  597)  in  large  squares. 

Lens  paper—  Japanese. 

Cylinder  graduates — 25  c.c,  50  c.c,  100  c.c,  500  c.c,  1000  c.c. 

Fermentation  tubes,  Smith  pattern,  or  Hill  pattern. 

Thermometers,  for  incubator;  for  oven;  for  autoclave  •  for  ordinary  purposes,  say 
6,  ranging  from  30°  C.  to  no0  C,  and  2,  ranging  from  ioo°  C.  to  300 J  C. 

Cork  borer  and  sharpener. 

Test  tube  brushes,  with  sponge  at  end,  bristles  at  side. 

Pinch-cocks  for  rubber  tubing. 

Blast  lamp  for  blowing  glass,  bending  tubes,  etc. 

Stain  bottles  (i.  e.,  rubber  nippled  pipette  bottles,  t  to  2  oz.  capacity. 

Absorbent  cotton,  for  filtering. 

Non-absorbent  cotton.  First  grade  cotton,  for  plugging  test  tubes,  etc. ;  second  grade,  for 
tumblers,  etc. 

Fuchsia,  basic,  Griibler  10  grams  Immersion  oil. 

Methylene  bine         "        10       "  Glycerine. 

Carbolic  acid  -phenol  -1st  grade  1  lb.  Canada  balsam. 

Aniline  oil  Griibler    i  oz.  Thread  agar — best. 

Gentian  violet  "        10  grams  Gold  label  gelatin  in  sheets — 10  lbs. 

Iodine  10      "  Hydrochloric  acid  1  lb. 

Potassium  iodide  1  oz.  Sodium  hydrate       1  lb. 

Alcohol  96^  ethyl  1  gal. 

Xylol  for  cleaning  lenses  2  oz. 

Test  tubes:  6"  x  f,  without  lip,  of  good  "  non-crystallizable  glass  "  (Boston  Board  of 
Health  pattern);  they  should  be  plugged  with  cotton  and  sterilized  in  hot  air  as 
below.  A  few  test  tubes  should  be  graduated  and  marked  at  9.  c.c.  capacity  and  kept 
for  dilution  purposes. 

Pipettes:  1  c.c.  mark,  discharge  pipettes,  about  10— 11  inches  long,  3  mm.  inside  diameter, 
are  the  best.  These  may  be  enclosed  in  long  tubes  one  in  each,  of  glass,  sealed  at 
one  end,  stoppered  with  cotton  at  the  other  ;  or  the  point  may  rest  on  a  cotton  wad 
at  the  bottom  of  a  test  tube,  the  mouth  of  the  test  tube  being  plugged  with  cotton 
round  the  stem,  a  small  cotton  plug   being  inserted  into    the   mouth  of  the  pipette 


280  CLEAN  MILK 

also;  or  they  may  be  placed  loose  in  cylindrical  (better  square)  copper  cr  tin  boxes 
(with  lapped  or  folded,  not  soldered  seams)  a  little  longer  than  the  pipette ;  or 
they  may  be  simply  wrapped  individually  in  filter  paper.  However  prepared,  they 
should  be  sterilized  in  the  hot  air  oven  for  one  hour  at  i6o°  C.  (or  2002  C.  for  30 
minutes),  or  until  a  wad  of  cotton  placed  beside  them  as  an  indicator  becomes  slightly 
browned  by  the  heat. 

Flasks  (preferably  of  the  Erlenmeyer  pattern)  of  good  Bohemian  glass  with  wide  necks 
and  tlat  thin  bottoms,  1  liter  capacity.     Plug  with  cotton  and  sterilize  in  hot  air. 

Bottles — S  oz.  Blake's,  square,  wide  mouthed,  marked  (by  a  file,  or  diamond,  but  best 
with  hydrofluoric  acid)  at  99  ex.  capacity  for  dilution  water.  Plug  with  cotton  and 
sterilize  in  hot  air. 

Petri  dishes — 4"  (10  cm.)  glass  bottoms,  with  porous  covers  to  match.  Wrap  in  soft 
paper  or  place  in  sets  of  10  in  a  covered  cardboard  box  for  sterilization  by  dry  heat. 

Incubator.  If  gas  is  available,  a  Koch  safety  burner  and  Lautenschlager  ether-mercury 
gas  regulator  may  be  used.  Fair  results  have  been  obtained  where  gas  was  not 
available  by  using  an  ordinary  chicken  incubator  carefully  regulated  and  watched 
daily. 

Counting  apparatus.  That  of  the  International  Instrument  Co.  (Boston  Board  of  Health 
pattern)  or  Stewart's  counter,  are  good.  A  home-made  one  quite  efficient  for  the 
finest  work  may  be  made  from  a  child's  school  slate,  on  which  is  scratched  a  four- 
inch  circle,  divided  by  four  cross  lines  into  eighths ;  a  box  about  4^  to  5  inches  square, 
about  4  inches  high,  without  a  bottom,  to  rest  on  the  slate  over  the  square,  and 
having  one  side  (to  face  the  window)  glass,  the  top  perforated  by  a  hole  3^"  in  dia- 
meter, on  which  a  4"  reading  glass  rests ;  the  height  of  the  box  to  correspond 
with  the  practical  focus  of  the  lens,  which  may  be  determined  readily  before- 
hand (/.  e.,  the  distance  which  the  lens  should  be  from  the  object  examined 
in  order  to  give  a  clear  magnified  image  to  the  observer  with  his  eye  at  a  convenient 
distance  from  the  lens).  To  count  a  plate,  place  the  plate  upon  the  circle  marked 
on  the  slate,  centering  it  carefully;  remove  the  cover;  place  the  box  over  it,  with 
the  glass  front  towards  the  window  and  the  reading  lens  over  the  circular  opening 
in  the  top  :  and  count  all  the  colonies  visible,  using  the  divisions  of  the  circle  merely 
as  an  aid  to  prevent  recounting  the  same  colony.  It  is  well  to  number  the  divisions 
and  always  to  begin  counting  at  division  No.  1,  in  order  that  the  same  division 
should  not  be  counted  twice.  Of  course,  once  the  counting  has  begun,  the  plate 
must  not  be  permitted  to  shift  on  the  lines  even  to  a  very  slight  extent. 

Microscope.  A  microscope  is  not  essential  to  bacterial  work  on  milk,  so  long  as  species 
differentiation  is  not  attempted,  and  much  valuable  information  bearing  on  clean 
milk  can  be  demonstrated  by  a  beginner  to  himself  through  methods  hereinbefore 
described  without  ever  seeing  an  isolated  bacterial  cell — in  other  words,  by  dealing 
wholly  with  mass  growths  of  bacteria,  cultures,  colonies,  etc.  If  a  microscope  is  de- 
sired, however,  a  good  instrument  should  be  bought  from  standard  makers,  Ameri- 
can or  foreign—a  monocular  tube,  with  fine  adjustment,  substage  condenser,  iris 
diaphragm  and  oil-immersion  lens  covering  the  essentials.  A  combination  of  lenses 
giving  great  satisfaction  in  practice  consists  of:  objectives,  ^  oil  immersion;  £ 
"dry,"  and  J  "dry";  and  oculars  Nos.  1  and  4  or  equivalents.  A  triple  nosepiece  is 
not  necessary,  although  a  great  convenience  ;  a  mechanical  stage  is  needed  only 
for  refined  work.  A  satisfactory  instrument  for  all  ordinary  work  may  be  had  at 
from  $70  to  $100.  Books  describing  the  care  and  use  of  the  microscope  may 
be  had,  notably  by  Gage  and  by  Wright  (Gage — "  The  Microscope,"  Comstock 
Publishing  Co.,  Ithaca  N.  Y.;  Wright — "  Principles  of  Microscopy,"  MacMillan  Co., 
New  York). 


CHAPTER  XIII 


CLASSIFICATION  AND  IDENTIFICATION  OF  BAD 
TERIA— GLOSSARY-ADJUSTMENT  OF  REAC- 
TION OF   MEDIA 


MIGULA-CHESTER  CLASSIFICATION. 

(Arranged  by  H.  W.  Hill.) 

(Giving  the  families  and  genera  by  name ;  and  the  number  of  species  in  each  genus, 
as  described  in  Chester's  Manual.) 

BACTERIA. 

Branched. 

MYCOBACTERIACEiE 

growth  axis  filamentous Streptothrix  18  Species 

growth  axis  not  filamentous Mycobacterium  19         " 

Not  branched 
growth  axis  filamentous 

cells  sheathed chlamydobacteriacE/E 

sulphur  granules Thiothrix                            I         «* 

no  sulphur  granules 

filaments  pseudo-branched Cladothrix                        10        • 

filaments  not  pseudo-branched 

cell-division  in  1  plane Leptothrix                         6        u 

cell-division  in  3  planes 

sheath  delicate Phragmidiothrix               I         " 

sheath  well-developed Crenothrix                         1         " 

cells  not  sheathed  beggiatoace^ 

Beggiatoa  4        «• 

growth  axis  not  filamentous 
growth  axis  ^>  transverse  axis 


Note— Families  in  capitals  ;  genera  in  small  letters. 
2S1 


282  CLEAN  MILK 

growth  axis  spiral , spirillace^ 

cell  flexile Spirochaeta                       5  Species 

cell  not  flexile 
flagellate 

three  or  less,  polar Microspira                        20         " 

bundle,  polar Spirillum                           13         " 

not  flagellate Spirosoma                          5        " 

growth  axis  not  spiral BACTERIACe;e 

flagellate 

peritrichic Bacillus                           275         " 

polar Pseudomonas                  47         " 

not  flagellate Bacterium                       216        " 

growth  axis  not  ^>  transverse  axis coccace^ 

flagellate 

cell-div.  in  2  planes Planococcus                       3        " 

cell  div.  in  3  planes Planosarcina                       3         " 

not  flagellate 

cell-div.  in  1  plane Streptococcus                 36        " 

cell-div.  in  2  planes Micrococcus                    91         " 

cell-div.  in  3  planes Sarcina                            14        " 


SCHEME   FOR    EXAMINATION   OF   PURE   BACTERIAL   CULTURES, 
FOR  IDENTIFICATION  OF  SPECIES 

(Adopted  by  the  Society  of   American  Bacteriologists,  Dec.  31,  '07  :  Committee 
on  Identification  of  Species,  Chester,  Gorham  and  E.  T.  Smith. ) 

I.   MORPHOLOGY. 

1.  Vegetative  Cells. — Medium  used;  temperature ;  age  in  days.    Form,  round, 

short  rods,  long  rods,  short  chains,  long  chains,  filaments,  commas,  short 
spirals,  long  spirals,  Clostridium,  aincate,  clavate,  curved.    Limits  of  size. 
Size  of  majority.     Ends,  rounded,  truncate,  concave. 
Agar  Hanging-Block. — Orientation  (grouping).     Chains  (No.  of  elements). 
Short  chains,  long  chains.     Orientation  of  Chains,  parallel,  irregular. 

2.  Sporangia. — Medium  used;  temperature  ;  age  in  days.    Form,  elliptical,  short 

rods,  spindled,  clavate,  drumsticks.     Limits  of  Size.     Size  of  Majority. 
Agar  Hanging-Block. — Orientation  (grouping).     Chains  (No.  of  elements). 

Orientation  of  Chains,  parallel,  irregular. 
Location  of  Endospores,  central,  polar. 

3.  Endospores. — Form,  round,  elliptical,  elongated.     Limits  of  Size.     Size  of 

Majority.     Wall,  thick,  thin.     Sporangium  wall,  adherent,  not  adherent. 

Germination,  equatorial,  oblique,  polar,  bipolar,  by  stretching. 
A.   Flagella. — No.;   Attachment,  polar,  bipolar,  peritrichiatc.     How  Stained. 
5.  Capsules. — Present  on. 
€.  Zoogloea. — Pseudozoogloea. 
7.  Involution  Forms. — On;  in days  at °C. 


CLASSIFICATION  OF  BACTERIA  283. 

8.  Staining  Reactions. — 1:10  watery  fuchsin,  gentian  violet,  carbol  fuchsin, 
Loeffler's  alkaline  methylene  blue.  Special  Stains:  Gram;  Glycogen; 
Fat;  Acid  fast;  Neisser. 

II.     CULTURAL  FEATURES. 

1.  Agar   Stroke. — Growth,   invisible,  scanty,   moderate,   abundant.     Form   of 

growth,  filiform,  echinulate,  beaded,  spreading,  plumose,  arborescent, 
rhizoid.  Elevation  of  growth,  Hat,  effuse,  raised,  convex.  Lustre,  glisten- 
ing, dull,  cretaceous.  Topography,  smooth,  contoured,  rugose,  verrucose. 
Optical  Characters,  opaque,  translucent,  opalescent,  iridescent.     Chromo- 

genesis.      Odor,    absent,    decided,    resembling Consistency,    slimy, 

butyrous,  viscid,  membranous,  coriaceous,  brittle.  Medium,  grayed, 
browned,  reddened,  blued,  greened. 

2.  Potato. — Growth,  scanty,  moderate,  abundant,  transient,  persistent.     Form 

of  growth,  filiform,  echinulate,  beaded,  spreading,  plumose,  arborescent, 
rhizoid.  Elevation  of  growth,  flat,  effuse,  raised,  convex.  Lustre,  glisten- 
ing, dull,  cretaceous.  Topography,  smooth,  contoured,  rugose,  verrucose, 
Chromogenesis.  Pigment  in  water,  insoluble,  soluble;  other  solvents. 
Odor,  absent,  decided,  resembling. .  .Consistency,  slimy,  butyrous,  viscid, 
membranous,  coriaceous,  brittle.  Medium,  grayed,  browned,  reddened, 
blued,  greened. 

3.  Loeffler's    Blood    Serum. — Stroke,    invisible,   scanty,   moderate,   abundant. 

Form  of  growth,  filiform,  echinulate,  beaded,  spreading,  plumose,  arbores- 
cent, rhizoid.  Elevation  of  growth,  flat,  effuse,  raised,  convex.  Lustre, 
glistening,  dull,  cretaceous.  Topography,  smooth,  contoured,  rugose, 
verrucose.  Chromogenesis.  Medium,  grayed,  browned,  reddened,  blued, 
greened.     Liquefaction  begins  in....d,  complete  in....d. 

4.  Agar  Stab. — Growth,  uniform,  best  at  top,  best  at  bottom;  surface  groivth 

scanty,  abundant;  restricted,  wide-spread.  Line  of  puncture,  filiform, 
beaded,  papillate,  villous,  plumose,  arborescent;  liquefaction. 

5.  Gelatin    Stab. — Growth,  uniform,   best   at   top,   best   at    bottom.     Line    of 

puncture,  filiform,  beaded,  papillate,  villous,  plumose,  arborescent.  Lique- 
faction, cratcriform,  napiform,  infiiudibuliform,  saccate,  stratiform;  begins 
in d,  complete  in d.     Medium,  fluorescent,  browned. 

6.  Nutrient    Broth. — Surface  growth,   ring,  pellicle,  flocculent,   membranous, 

none.  Clouding,  slight,  moderate,  strong;  transient,  persistent;  none; 
fluid  turbid.  Odor,  absent,  decided,  resembling.  . .  Sediment,  compact, 
Hocculent,  granular,  flaky,  viscid  on  agitation,  abundant,  scant. 

7.  Milk. — Clearing  without  coagulation.    Coagulation,  prompt,  delayed,  absent. 

Extrusion   of   whey   begins   in days.     Coagulum,  slozdy  peptonized, 

rapidly  peptonized.     Peptonization  begins  on d,  complete  on d. 

Reaction,  id,  2d,  4d,  iod,  20d.  Consistency,  slimy,  viscid,  unchanged. 
Medium,  browned, reddened,  blued,  greened.    Lab  ferment,  present,  absent. 

8.  Litmus   Milk. — Acid,  alkaline,  acid  then  alkaline,  no  change.     Prompt  re- 

duction, no  reduction,  partial  slow  reduction. 

9.  Gelatin  Colonies. — Growth  slow,  rapid.     Form,  punctiform,  round,  irregu- 

lar, ameboid,  mycelioid,  filamentous,  rhizoid.  Elevation,  fiat,  effuse,  raised, 
convex,  pulvinate,  cratcriform  (liquefying).  Edge,  entire,  undulate,  lobate, 
erose,  lacerate,  fimbriate,  filamentous,  floccose,  curled.  Liquefaction,  cup, 
saucer,  spreading. 


284  CLEAN  MILK 

10.  Agar   Colonies. — Growth,    slow,   rapid  (temperature).     Form,   punctifornt, 

round,  irregular,  ameboid,  myccloid,  filamentous,  rhizoid.  Surface  smooth, 
rough,  concentrically  ringed,  radiate,  striate.  Elevation,  flat,  effuse,  raised, 
convex,  pulvinate,  umbonatc.  Edge,  entire,  undulate,  lobate,  erosc,  lacerate, 
fimbriate,  Hoceose,  curled.  Internal  structure,  amorphous,  finely-,  coarsely 
granular,  grumosc,  filamentous,  floccosc,  curled. 

11.  Starch    Jelly. — Growth,  scanty,   copious.      Diastasic   action,  absent,  feeble, 

profound.     Medium  stained. 

12.  Silicate    Jelly     (Fermi's    Solution). — Growth,   copious,    scanty,    absent. 

Medium  stained. 

13.  Conn's   Solution. — Growth,  copious,  scanty,  absent.     Medium,  fluorescent, 

non-fluorescent. 

14.  Uschinsky's    Solution. — Growth,  copious,    scanty,    absent.      Fluid,  viscid, 

not  viscid. 

15.  Sodium  Chloride  in   Bouillon. — Per  cent  inhibiting  growth. 

16.  Growth   in   Bouillon  over  Chloroform,  unrestrained,  feeble,  absent. 

17.  Nitrogen. — Obtained    from   peptone,   asparagin,   glycocoll,   urea,   ammonia 

salts,  nitrogen. 

18.  Best  media  for  long-continued  growth. 

19.  Quick  tests  for  differential   purposes. 

III.     PHYSICAL  AND  BIOCHEMICAL  FEATURES. 

1.  Gas  Production  from  Sugar. —  (a)  Amount  in  percentage  of  tube  length 

(closed  arm  of  fermentation  tube),  (b)  H/CO2  formula,  (c)  Acidity 
by    titration,   dextrose,  saccharose,  lactose,  maltose,  glycerin,  mannit. 

2.  Ammonia   production,  feeble,  moderate,  strong,  absent,  masked  by  acids. 

3.  Nitrates  in   nitrate  broth. — Reduced,  not  reduced.     Presence  of  nitrites; 

ammonia ;  presence  of  nitrates  ;  free  nitrogen. 

4.  Indol  production,  feeble,  moderate,  strong. 

5.  Toleration  of  Acids:    great,  medium,  slight.    Acids  tested. 

6.  Toleration  of  Na  O  H:    great,  medium,  slight. 

7.  Optimum    reaction   for  growth    in    bouillon,   stated  in  terms  of  Fuller's 

scale. 

8.  Vitality  on  culture  media:    brief,  moderate,  long. 

9.  Temperature    relations. — Thermal    death  point    (10   minutes   exposure   in 

nutrient    broth    when   this    is    adapted    to   growth    of    organism) C. 

Optimum   temperature    for   growth C.  ;    or   best   growth   at    i$°  C.„ 

20 °  C,  25'  C,  30"  C,  370  C,  40  "C,  50°  C,  6o°  C.  Maximum  temperature 
for  growth C.     Minimum  temperature  for  growth C. 

10.  Killed  readily  by  drying:  resistant  to  drying. 

11.  Per  cent,  killed  by  freezing   (salt  and  crushed  ice  or  liquid  air). 

12.  Sunlight:     Exposure    on    ice    in    thinly    sown    agar    plates:    one-half   plate 

covered  (time  15  minutes),  sensitive,  not  sensitive.     Per  cent  killed. 

13.  Acids  produced. 

14.  Alkalies  produced. 

15.  Alcohols. 

16.  Ferments;    pepsin,   trypsin,   diastase,   invertase,  pectase,  cytase.   tyrosinase, 

oxidase,  peroxidase,  lipase,  catalase,  glucasc,  galactose,  lab,  etc. 

17.  Crystals  formed. 

18.  Effect  of  germicides. 


CLASSIFICATION  OF  BACTERIA  285 

IV.     PATHOGENICITY. 

1.  Pathogenic  to  Animals. — Insects,  crustaceans,  fishes,  reptiles,  birds,  mice, 

rats,  guinea  pigs,  rabbits,  dogs,  cats,  sheep,  goats,  cattle,  horses,  monkeys, 
man. 

2.  Pathogenic  to  Plants. 

3.  Toxins,  soluble,  endotoxins. 

4.  Non-toxin  forming. 

5.  Immunity    bactericidal. 

6.  Immunity    non-bactericidal. 

7.  Loss    of    virulence    on    culture    media:    prompt,   gradual,    not    observed- 

in months. . 


GLOSSARY  OF  BACTERIOLOGICAL  TERMS  USED  IN  DESCRIBING  AND 
IDENTIFYING  SPECIES  OF  BACTERIA. 

(Committee  on  Identification  of  Species  :  Soc.  Am.  Bact.) 

AGAR  HANGING  BLOCK,  a  small  block  of  nutrient  agar  cut  from  a  poured 
plate,  and  placed  on  a  cover-glass,  the  surface  next  the  glass  having  been 
first  touched  with  a  loop  from  a  young  fluid  culture  or  with  a  dilution  from 
the  same.     It  is  examined  upside  down,  the  same  as  a  hanging  drop. 

AMEBOID,  assuming  various  shapes  like  an  ameba. 

AMORPHOUS,  without  visible  differentiation  in  structure. 

ARBORESCENT,  a  branched,  tree-like  growth. 

BEADED,  in  stab  or  stroke,  disjointed  or  semi-confluent  colonies  along  the  line 
of  inoculation. 

BRIEF,  a  few  days,  a  week. 

BRITTLE,  growth  dry,  friable  under  the  platinum  needle. 

BULLATE,  growth  rising  in  convex  prominences,  like  a  blistered  surface. 

BUTYROUS,  growth  of  a  butter-like  consistency. 

CHAINS, —  Short  chains,  composed  of  2  to  8  elements.  Long  chains,  composed 
of  more  than  8  elements. 

CI  LI  ATE,  having  fine,  hair-like  extensions,  like  cilia. 

CLAVATE,  club-shaped. 

CLOUDY,  said  of  fluid  cultures  which  do  not  contain  pseudozoogloeae. 

COAGULATION,  the  separation  of  casein  from  whey  in  milk.  This  may  take 
place  quickly  or  slowly,  and  as  the  result  either  of  the  formation  of  an  acid 
or  of  a  lab  ferment. 

CONTOURED,  an  irregular,  smoothly  undulating  surface,  like  that  of  a  relief 
map. 

CONVEX,  surface  the  segment  of  a  circle,  but  flattened. 

COPROPHYL,  dung  bacteria. 

CORIACEOUS,  growth  tough,  leathery,  not  yielding  to  the  platinum  needle. 

CRATERIFORM,  round,  depressed,  due  to  the  liquefaction  of  the  medium. 

CRETACEOUS,  growth  opaque  and  white,  chalky. 

CUNEATE,  wedge-shaped. 

CURLED,  composed  of  parallel  chains  in  wavy  strands,  as  in  anthrax  colonies.. 


286  CLEAN  MILK 

DIASTASIC  ACTION,  same  as  DIASTATIC,  conversion  of  starch  into  water- 
soluble  substances  by  diastase. 

ECHINULATE,  in  agar  stroke  a  growth  along  line  of  inoculation,  with  toothed 
or  pointed  margins;  in  stab  cultures  growth  beset  with  pointed  outgrowths. 

EFFUSE,  growth  thin,  veily,  unusually  spreading. 

ENTIRE,  smooth,  having  a  margin  destitute  of  teeth  or  notches. 

EROSE,  border  irregularly  toothed. 

FILAMENTOUS,  growth  composed  of  long,  irregularly  placed  or  interwoven  fila- 
ments. 

FILIFORM,  in  stroke  or  stab  cultures  a  uniform  growth  along  line  of  inoculation. 

FIMBRIATE,  border  fringed  with  slender  processes,  larger  than  filaments. 

FLOCCOSE,  growth  composed  of  short  curved  chains,  variously  oriented. 

FLOCCULENT,  said  of  fluids  which  contain  pseudozoogloeae,  *.  e.,  small  ad- 
herent masses  of  bacteria  of  various  shapes  and  floating  in  the  culture  fluid. 

FLUORESCENT,  having  one  color  by  transmitted  light  and  another  by  reflected 
light. 

GRAM'S  STAIN,  a  method  of  differential  bleaching  after  gentian  violet,  methyl 
violet,  etc.  The  +  mark  is  to  be  given  only  when  the  bacteria  are  deep 
blue  or  remain  blue  after  counterstaining  with  Bismark  brown. 

GRUMOSE,  clotted. 

INFUNDIBULIFORM,  form  of  a  funnel  or  inverted  cone. 

IRIDESCENT,  like  mother-of-pearl.       The  effect  of  very  thin  films. 

LACERATE,  having  the  margin  cut  into  irregular  segments  as  if  torn. 

LOBATE,  border  deeply  undulate,  producing  lobes  (see  undulate). 

LONG,  many  weeks,  or  months. 

MAXIMUM  TEMPERATURE,  temperature  above  which  growth  does  not  take 
place. 

MEDIUM,    (time)  several  weeks. 

MEMBRANOUS,  growth  thin,  coherent,  like  a  membrane. 

MINIMUM  TEMPERATURE,  temperature  below  which  growth  does  not  take 
place. 

MYCELIOID,  colonies  having  the  radiately  filamentous  appearance  of  mold 
colonies. 

NAPIFORM,  liquefaction  with  the   form  of  a  turnip. 

NITROGEN  REQUIREMENTS,  the  necessary  nitrogenous  food.  This  is 
determined  by  adding  to  nitrogen-free  media  the  nitrogen  compound  to  be 
tested. 

OPALESCENT,  resembling  the  color  of  an  opal. 

OPTIMUM  TEMPERATURE,  temperature  at  which  growth  is  most  rapid. 

PELLICLE,  in  fluid  bacterial  growth  either  forming  a  continuous  or  an  inter- 
rupted sheet  over  the  fluid. 

PEPTONIZED,  said  of  curds  dissolved  by  trypsin. 

PERSISTENT,  many  weeks,  or  months. 

PLUMOSE,  a  fleecy  or  feathery  growth. 

PSEUDOZOOGLOEAE,  clumps  of  bacteria,  not  dissolving  readily  in  water, 
arising  from  imperfect  separation,  or  more  or  less  fusion  of  the  components, 
but  not  having  the  degree  of  compactness  and  gelatinization  seen  in 
zoogloeae. 

PULVINATE,  in  the  form  of  a  cushion,  decidedly  convex. 

PUNCTIFORM,  very  minute  colonies,  at  the  limit  of  natural  vision. 


CLASSIFICATION  OF  BACTERIA  287 

RAISED,  growth  thick,  with  abrupt  or  terraced  edges. 

RHIZOID,  growth  of  an  irregular  branched  or  root-like  character,  as  ir» 
B.  mycoides. 

RING,  same  as  RIM,  growth  at  the  upper  margin  of  a  liquid  culture,  adhering; 
more  or  less  closely  to  the  glass. 

REPAND,  wrinkled. 

RAPID,   developing  in  24  to  48  hours. 

SACCATE,  liquefaction  the  shape  of  an  elongated  sack,  tubular,  cylindrical. 

SCUM,  floating  islands  of  bacteria,  an  interrupted  pellicle  or  bacterial  membrane. 

SLOW,  requiring  5  or  6  days  or  more  for  development. 

SHORT,  applied  to  time,  a  few  days,  a  week. 

SPORANGIA,  cells  containing  endospores. 

SPREADING,  growth  extending  much  beyond  the  line  of  inoculation,  i.  e.s  sev- 
eral millimeters  or  more. 

STRATIFORM,  liquefying  to  the  walls  of  the  tube  at  the  top  and  then  pro- 
ceeding downwards  horizontally. 

THERMAL  DEATH-POINT,  the  degree  of  heat  required  to  kill  young  fluid 
cultures  of  an  organism  exposed  for  10  minutes  (in  thin-walled  test  tubes 
of  a  diameter  not  exceeding  20  mm.)  in  the  thermal  water-bath.  The  water 
must  be  kept  agitated  so  that  the  temperature  shall  be  uniform  during  the 
exposure. 

TRANSIENT,  a  few  days. 

TRUNCATE,  flat-ended,  instead  of  tapering,  rounded,  or  concave. 

TURBID,  cloudy  with  flocculent  particles;  cloudy  plus  flocculence. 

UM  BON  ATE,  having  a  button-like,  raised  center. 

UNDULATE,  border  wavy,  with  shallow  sinuses. 

VERRUCOSE,  growth  wart-like,  with  wart-like  prominences. 

VERMIFORM-CONTOURED,  growth  like  a  mass  of  worms,  or  intestinal  coils. 

VILLOUS,  growth  beset  with  hair-like  extensions. 

VISCID,  growth  follows  the  needle  when  touched  and  withdrawn,  sediment  on 
shaking  rises  as  a  coherent  swirl. 

ZOOGLOEAE,  firm,  gelatinous  masses  of  bacteria,  one  of  the  most  typical  exam- 
ples of  which  is  the  Streptococcus  niesenterioides  of  sugar  vats  {Leuconosloc 
mcscnterioides),  the  bacterial  chains  being  surrounded  by  an  enormously 
thickened  firm  covering,  inside  of  which  there  may  be  one  or  many  groups 
of  the  bacteria. 


ADJUSTMENT  OF  REACTION  OF   MEDIA  BY  TITRATION  WITH 
PHENOLPHTHALEIN. 

Required  Apparatus  and  Solutions. — Two  burettes  (Fig-.  69), 
(one  at  least  with  a  rubber  tube  outlet  for  the  alkali ;  the  other  may 
have  a  glass  cock).  A  six-inch  porcelain  exaporating  dish,  with 
tripod,  wire  gauze  and  stirring  rod.  A  Bunsen  burner,  cylinder 
graduate,  and  5  c.c.  pipette.     Normal  NaOH  solution,  normal  HCl 


288 


CLEAN  MILK 


solution  and  twentieth  normal  solutions  of  each,  in  well  stoppered 
bottles,  those  containing  the  alkali  stoppered  with  rubber,  and  pro- 
tected with  soda-lime  (or  KOH)  U-tubes.  Phenolphthalein  solu- 
tion (J4%  phenolphthalein  (powder)  in  50%  alcohol,  i.  c,  1  gram 
phenolphthalein,  alcohol  100,  water  100),  and  a  1  c.c.  pipette. 

Fig.  69. 


Two  burettes  arranged  for  titrating  culture  media. 


Process. — Set  the  evaporating  dish  on  the  gauze,  the  gauze  orr 
the  tripod,  and  measure  into  the  dish  5  c.c.s  of  the  media  to  be  di- 
trated.  Add  45  c.c.s  of  distilled  water.  Boil  freely  one  minute  to 
expel  C02 ;  lower  the  flame  until  the  liquid  merely  simmers ;  add  1 
c.c.  phenolphthalein  solution;  if  no  pink  color  develops,  the  media  is 


CLASSIFICATION  OF  BACTERIA  289 

acid  ;  a  pink  color  shows  it  to  be  alkaline.  If  acid  (as  is  usual),  run 
in  from  the  burette,  drop  by  drop,  stirring  the  mixture  constantly, 
N/20  NaOH  until  a  faint,  permanent,  pink  develops.  The  amount 
of  N/20  NaOH  used  to  produce  this  color  if  read  in  c.c.s  and  frac- 
tions, gives  directly  the  percentage  of  normal  alkali  theoretically 
needed  to  neutralize  the  medium ;  the  same  figure  indicates  the 
^percentage  acidity  (in  normal  acid)  of  the  medium  as  it  is  at  the 
moment.  The  difference  between  the  existing  percentage  acidity  of 
the  medium  and  the  percentage  acidity  desired,  read  in  c.c.s  and 
fractions,  indicates  the  amount  of  normal  alkali  or  acid  per  100 
c.c.s  of  media  which  should  (theoretically)  be  added,  to  attain  the 
desired  reaction. 

Examples  of  Titration  of  Media. — 1.  If  the  filtrate  (Step  3 
schedule  given  above  for  making  the  principal  artificial  media)  be 
titrated  it  will  prove  to  be  about  2.5%  acid.    The  steps  are: 

(a)  Remove  5  c.c.s  to  the  evaporating  dish;  add  45  c.c.a. 
neutral  water.  (The  water  is  added  merely  to  give  enough  bulk. 
to  boil,  without  too  much  evaporation  or  burning  of  the  media, 
as  might  occur  if  5  c.c.s  of  media,  undiluted,  were  used.)  The 
absolute  quantity  of  water  added  is  of  no  moment,  but  it  is  im- 
portant that  the  same  quantity  be  used  in  each  titration,  since  the 
color  developed  when  the  phenolphthalein  turns  pink  will  vary  in 
depth  if  the  amounts  of  water  added  vary  because  of  the  variations 
in  dilution  thus  introduced.) 

(b)  Boil  1  minute;  the  albumens  coagulate  and  the  reddish 
color  of  the  meat  infusion  diluted  by  the  added  water  largely 
disappears. 

(c)  Add  1  c.c.  phenolphthalein  solution. 

(d)  To  the  still  simmering  mixture  add  N/20  NaOH  as  de- 
scribed above. 

(e)  If  2.5  c.c.s  of  N/20  NaOH  are  necessary  to  neutralize  the 
5  c.c.s  of  meat  infusion,  2.5  c.c.s  of  normal  NaOH  (twenty  times 


290  CLEAN  MILK 

as  strong  as  N/20  NaOH)  will  be  required  to  neutralize  ioo  c.c.s  of 
the  infusion  (twenty  times  as  much  as  the  five  c.c.s  actually  tested). 
Since  2.5  c.c.s  normal  acid  are  (theoretically)  necessary  to 
neutralize  100  c.c.s  of  the  infusion  (in  the  case  under  considera- 
tion), the  reaction  of  the  infusion  would  be  stated  as  equivalent 
to  2.5  c.c.s  of  normal  acid  per  100;  or,  briefly,  "the  infusion  is 
2.5%  acid." 

(f)  The  addition  of  the  peptone  (Step  3)  scarcely  alters  the 
acidity  as  a  rule:  nor  do  the  constituents  mentioned  under  5(a) 
and  5(b)  ;  but  the  addition  of  gelatin  5  (c)  and  the  action  of  B.  coli 
5(d)  add  considerably  to  the  original  acidity,  as  a  rule.  Hence 
the  necessity  for  Step  6,  which  is  thus  performed:  (1)  Determine 
the  existing  acidity;  suppose  it  to  prove  2.89^  acid.  (2)  Adjust 
to  1.5$  acid  thus:  2.8 — 1.5  =  1.3;  hence  add  to  the  medium  1.3 
c.c.s  normal  alkali  per  100  c.c.s.  Theoretically,  titration  of  the 
medium  should  now  show  1.5%  acid.  In  practice  the  acidity  will 
prove  to  be  higher,  say  1.8%.  As  the  desired  reaction  is  1.5  this 
means  that  (1.8 — 1.5)  .3  c.c.s  normal  alkali  per  100  c.c.s  medium 
must  still  be  added.  Usually  titration  after  this  addition  will  yield 
the  desired  1.5%  acidity.  If  the  acidity  be  still  too  high  (say 
j.6  then  1.6 — 1.5  =  .1 )  .1  c.c.s  normal  alkali  per  100  c.c.s  media 
must  be  added,  and  titration  now  will  show  that  the  desired  point 
has  at  last  been  reached.  Should  any  accident  such  as  the  ad- 
dition of  too  much  normal  alkali  occur,  by  which  the  medium  is 
adjusted  to  a  point  below  the  point  sought  (i.  c,  1%  acid,  when 
1.5%  is  desired)  the  difference  between  the  existing  acidity  and 
the  acidity  sought  will  indicate  the  (theoretical)  amount  of  normal 
acid  to  be  added  per  100  c.c.s  of  media,  to  restore  it  to  the  desired 
acidity  (i.  c,  .5  c.c.s  normal  acid  in  the  case  quoted).  But  media 
in  the  preparation  of  which  any  such  departure  from  the  regular 
course  occurs  should  not  be  used  for  official  or  research  work  on 
counts. 

Note :  Normal  NaOH  is  prepared  in  such  a  manner  as  to  secure 


CLASSIFICATION  OF  BACTERIA  291 

a  pure  aqueous  solution  of  NaOH  containing  exactly  40  grams  per 
litre.  Beginners  often  attempt  to  make  the  solution  by  weighing 
40  grams  of  sodium  hydrate  sticks,  dissolving  in  700 — 800  c.c. 
water  and  making  up  to  1  litre,  or  even  by  adding  40  grams  directly 
to  1  litre  of  water.  Unfortunately,  sodium  hydrate  is  so  hygros- 
copic that  in  the  very  process  of  weighing  it  will  absorb  water  from 
the  atmosphere  sufficient  to  change  its  weight,  so  that  it  is  impossible 
thus  to  prepare  an  accurate  solution.  A  sufficiently  accurate  normal 
NaOH  solution  may  be  prepared  (if  pure  oxalic  acid  is  available) 
by  dissolving  62.5  grams  of  oxalic  acid  in  700 — 800  c.c.  water, 
making  up  exactly  to  1  litre.  This  constitutes  a  normal  acid  solu- 
tion. Dissolve  about  50  to  60  grams  NaOH,  weighed  quickly  and 
roughly  in  700  to  800  c.c.  of  recently  boiled  water  (thus  securing  a 
solution  C02-free,  and  somewhat  stronger  than  normal).  Titrate 
the  inexact  NaOH  solution  against  the  exact  oxalic  acid  solution, 
using  the  phenolphthalein  solution  as  an  indicator;  it  will  be  found 
that  5  c.c.s  (say)  of  the  NaOH  require  for  neutralization  (say) 
7  c.c.s  of  the  oxalic  acid  solution;  hence  5  c.c.s  of  NaOH  solution 
should  be  diluted  to  7  c.c.s  with  water,  in  order  that  it  should  exactly 
equal  in  strength  the  oxalic  acid  solution.  Hence  800  c.c.s  (say)  of 
the  NaOH  solution  should  be  diluted  to  (7/5  of  800)  1,120  c.c.s  in 
order  to  equal  in  strength,  c.c.  for  c.c,  the  oxalic  acid  solution. 
Dilute  with  great  care  to  a  point  somewhat  short  of  the  calculated 
figure  (say,  to  1,050  c.c.s,)  and  again  titrate.  If  the  NaOH  solu- 
tion still  proves  too  strong  (say  that  5  c.c.  of  the  NaOH  solution 
now  require  5.5  c.c.s  of  oxalic  acid  solution  for  neutralization), 
dilute  again  in  the  proportions  thus  indicated,  5.5/5  of  1,045  (a^~ 
lowing  for  the  5  c.c.s  withdrawn  for  titration),  i.  c,  dilute  the  re- 
maining 1,045  c-c-s  °f  NaOH  solution  with  water  to  1,149.5  c.c.s 
and  check  again.  N20  solutions  are  prepared  by  accurately  diluting 
1  part  of  a  normal  solution  to  make  20  parts  in  all — i.  e.,  dilute  50 
c.c.s  normal  NaOH  with  distilled  water  to  make  one  litre. 

It  is  best  when  possible  to  have  the  normal  XaOH  prepared 


292  CLEAN  MILK 

by  an  expert  chemist,  who  will  probably  prefer  to  prepare  a  norma?' 
alkaline  solution  from  chemically  pure  sodium  carbonate,  fused ; 
a  normal  acid  solution  of  HC1  by  titration  against  this ;  and  a 
normal  NaOH  solution  by  titration  against  the  normal  HC1. 

To  prepare  a  normal  HC1  acid  solution  by  titration  against  the 
normal  NaOH  solution,  take  about  ioo  c.c.  of  chemically  pure 
hydrochloric  acid  (sp.  gr.  120)  and  dilute  to  1  litre,  making  thus 
a  solution  slightly  stronger  than  normal.  Titrate  this  against  the 
normal  NaOH  solution.  It  will  prove  to  be  stronger  and  the 
figures  obtained  will,  as  described  above,  for  the  making  of  normal 
NaOH  from  oxalic  acid,  indicate  how  much  it  should  be  diluted  to 
make  it  equal,  c.c.  for  c.c,  the  strength  of  the  normal  NaOH 
solution. 


CHAPTER  XIV 


LABORATORY  WORK  IN  DAIRY   BACTERIOLOGY* 

By  Professor  H.  W.  Conn 


THE  directions  for  these  experiments  are  given  in  sufficient 
detail,  so  that  anyone  with  a  fair  knowledge  of  laboratory- 
methods  can  follow  them  without  other  instruction.     The 
private  student  of  dairying  may,  therefore,  carry  out  this 
laboratory  course  by  himself,  although  it  will  take  more  time  in  this 
case  than  if  adequate  personal  instruction  were  obtained. 

Special  emphasis  should  be  placed  upon  the  necessity  of  care- 
fully labeling  every  culture  made  and  recording  in  a  note  book 
each  experiment,  its  purpose  and  results. 

PRACTICAL    WORK.f 

i.  J  J 'ashing  Glassware. — All  glassware  used  in  bacterio- 
logical work  must  be  thoroughly  washed.    No  special  directions  need 


*The  following  pages,  containing  practical  experiments  to  be  performed  in  the  labor- 
atory, are  taken  by  the  kind  permission  of  Prof.  Conn  from  his  Practical  Dairy  Bacterio- 
logy, published  by  Orange  Judd  Co.,  New  York. 

1  The  following  laboratory  manuals  may  be  found  useful  as  books  of  reference  : 

Moore.     Laboratory  Directions  for  Beginners  in  Bacteriology.     Ginn  &  Co.,  1900. 

Frost.     A  Laboratory  Guide  in  Elementary  Bacteriology.     The  Macmillan  Co.,  1903. 

Gorham.     A  Laboratory  Course  in  Bacteriology.     W.  B.  Saunders,  1901. 

Van  Slyke.  Methods  of  Testing  Milk  and  Its  Products.  Orange  Judd  Pub.  Co., 
T906.  Bacteriology  Of  Milk,  Swithinbank  and  Newman,  E.  P.  Dutton  &  Co.,  N.  Y.,  is 
the  most  elaborate  and  complete  work  on  the  subject,  containing  detailed  description 
and  beautiful  plates  of  bacteria  in  milk. — K.  W. 

293 


294  CLEAN  MILK 

be  given  save  that  hot  water  and  soap  are  necessary.  New  glass- 
ware should  be  treated  first  with  i%  HC1.  Used  glassware  that 
contains  the  remains  of  gelatin  or  other  media  must  first  be  boiled 
in  water,  preferably  containing  a  little  sal  soda  or  powdered  soap. 
After  boiling,  wash  well  in  hot  water  and  then  rinse  thoroughly 
in  clear  cold  water;  drain  and  allow  to  dry. 

2.  Comparison  of  Yeast  and  Bacteria. — Rub  up  in  a  watch 
glass  a  bit  of  a  cake  of  yeast  with  a  little  water.  Place  a  drop 
of  the  liquid  on  a  slide  and  examine  directly  with  the  microscope, 
using  a  ^-inch  objective.  Dry  a  little  of  the  material  on  a  slide 
and  stain  exactly  as  in  staining  bacteria  (No.  3).  Study  with  the 
immersion  lens,  comparing  the  yeast  cells  as  to  size  and  shape  with 
bacteria  already  studied.  Hunt  for  cells  showing  budding.  If  these 
are  not  found  they  may  be  obtained  in  quantity  by  planting  a  little 
yeast  in  a  weak  solution  of  molasses  in  water  and  allowing  to  grow 
for  a  few  hours  in  a  warm  place.  Make  a  sketch  of  the  yeast 
cells  with  buds,  showing  their  relative  size  to  that  of  bacteria. 

3.  Direct  Microscopic  Study  of  Milk. — For  this  a  centri- 
fuge is  needed,  having  tubes  with  straight  sides,  and  closed  at  the 
bottom  with  a  rubber  cork.  Place  2  c.c.  of  the  samples  of  milk 
to  be  tested,  after  thorough  shaking,  in  the  tubes.  It  is  necessary 
to  fill  enough  tubes  with  milk  from  different  samples,  to  balance 
the  centrifugal  machine  on  both  sides.  Rotate  in  the  machine 
at  a  rate  of  2,000  to  3,000  per  minute,  for  5  minutes.  Remove 
the  tubes  from  the  machine  and  they  will  be  found  to  have  a  layer 
of  cream  at  one  end,  and  a  small  slimy  deposit  at  the  other  end,  next 
the  cork.  Holding  the  tube  with  the  cream  end  clown,  remove  the 
cream  with  a  platinum  loop,  and  pour  out  the  milk  gently.  A  slimy 
sediment  will  be  left  attached  to  the  cork.  Carefully  remove  the 
cork  with  its  adhering  sediment,  and  smear  over  the  surface  of  a 
glass  slide,  with  a  drop  of  sterile  water,  to  cover  an  area  of  exactly 
four  square  centimeters.  Special  slides  marked  with  wax  pencils 
into  such  areas  are  needed.  'This  distribution  of  the  sediment  must 


LABORATORY  WORK  295 

be  carefully  done  in  order  that  it  should  be  uniform.  After  the 
thorough  distribution,  dry  in  gentle  heat,  or  without  heating,  and 
stain  by  flooding  the  surface  with  dilute  solution  of  methylene  blue 
for  a  short  time,  and  then  wash  the  stain  away.  After  again  drying, 
the  material  may  be  mounted  under  cover-glass,  or  it  may  be  exam- 
ined immediately  with  an  immersion  lens  without  a  cover-glass. 
There  will  be  found  on  the  slide  a  considerable  number  of  stained 
bacteria,  usually  showing  a  variety  of  forms,  and  also  a  varying 
number  of  large  cells,  most  of  which  have  deeply  stained  nuclei,  but 
unstained  bodies.  These  latter  are  leucocytes,  and  represent  cells  of 
the  character  of  the  white  blood  cells  from  the  cow,  which  have 
found  their  way  into  the  milk.  In  some  cases,  leucocytes  represent 
pus  cells  and  are  indicative  of  inflammatory  changes  in  the  animal's 
udder.  Y\  nere  the  numbers  are  small,  however,  they  give  no  such 
indication,  for  the  normal  milk  of  healthy  udders  will  usually  show 
considerable  numbers  of  these  leucocytes.  To  interpret  the  meaning 
of  what  is  found  under  the  microscope  in  these  preparations,  see 
section  4. 

4.  Doa  lie's  Method  of  Determining  Leucocytes. — Place 
10  c.c.  of  milk  in  the  tubes  of  a  centrifugal  and  rotate  at  about 
2,000  per  minute  for  four  minutes.  Carefully  remove  the  cream 
from  the  surface  with  a  bit  of  cotton  on  the  end  of  a  rod,  being 
careful  not  to  leave  any  of  the  cream  in  the  tube.  By  means  of  a 
small  siphon  remove  the  milk,  keeping  the  tip  of  the  tube  just  below 
the  surface  so  as  to  avoid  disturbing  the  sediment.  Siphon  away 
the  milk  to  within  about  one-eighth  of  an  inch  of  the  sediment.  Add 
two  drops  of  a  saturated  alcoholic  solution  of  methylene  blue  to  the 
tube,  and,  after  thoroughly  mixing,  place  the  tube  in  boiling  water 
for  two  minutes  to  aid  the  staining.  Add  enough  water  to  bring 
the  total  bulk  either  to  one  or  two  c.c,  according  to  the  amount  of 
sediment.  This  will  give  a  blue  mass  of  stained  sediments.  To 
count  their  number  an  ordinary  blood  counter  is  used.  This  will 
have  a  counting  chamber  marked  off  into  squares  and  holding  ex- 


296  CLEAN  MILK 

actly  one-tenth  of  a  cubic  millimeter.  Fill  this  counter  with  the 
stained  sediment,  cover  with  a  cover-glass,  allow  to  stand  for  about 
one  minute  for  the  leucocytes  to  settle,  and  then,  placing  under  a 
microscope,  count  the  number  of  leucocytes  found  in  a  single  ruled 
square  and  calculate  the  numbers  in  the  whole  chamber.  Remem- 
bering then  that  the  chamber  contains  one-tenth  of  a  cubic  milli- 
meter of  the  stained  sediment,  it  is  easy  to  calculate  the  number  of 
leucocytes  in  the  original  milk.  This  should  be  calculated  upon  the 
basis  of  a  certain  number  per  c.c,  and  good  milk  should  not  have 
more  than  500,000  per  c.c* 

5.  Separation  of  the  Common  Species  of  Bacteria  from 
Milk.  Allow  some  milk  to 'stand  at  about  700.  As  soon  as  it  be- 
gins to  sour,  but  before  it  curdles,  dilute  1  c.c.  500,000  times  and 
make  litmus  gelatin  plates.  .  Allow  to  grow  four  days  at  700  unless 
liquefiers  make  it  impossible. 

a.  Determine  the  total  number  of  bacteria  in  1  c.c.  of  milk. 

b.  Determine  the  number  of  acid  bacteria  per  c.c. 

c.  Determine  the  number  of  liquefiers  per  c.c. 

d.  Determine  the  percentages  in  each  case. 

e.  Isolate  a  colony  of  Bact.  lactis  acidi.  This  may  be  recog- 
nized as  follows :  It  is  an  intensely  acid  colony,  rather  opaque, 
always  below  and  never  on  the  surface.  It  is  small,  only  just 
visible  to  the  naked  eye  and  when  examined  under  a  low  power 
microscope  it  frequently,  though  not  always,  shows  a  slight  rough- 
ness, looking  like  minute  spines  around  its  edge.  With  a  platinum 
needle  lift  out  one  of  these  colonies  and  inoculate  into  a  gelatin 
tube  by  stabbing  the  needle  directly  into  the  gelatin.  After  growth, 
set  aside  for  future  use.f 


*  In  healthy  cows  the  leucocytes  in  milk  may  range  as  high  as  i,Soo,ooo  (Rus- 
sell i  1<>  4,500,000  (Savage).  In  healthy  cows  the  leucocytes  average  over  100,000 
(Savage),  or  2000,000  (Doane).  83^  of  cows  with  mastitis  (Russell)  yield  milk  con- 
taining over  500,000  leucocytes  per  c.c.  Prolonged  retention  of  milk  in  the  udder 
gives  rise  to  increased  leucocyte  content. — WiNsr.ow. 

t  For  special  characteristics,  see  Conn's  "  Practical  Dairy  Bacteriology." 


LABORATORY  WORK  297 

/.  Look  over  the  plates  made  in  this  experiment  and  see 
if  any  large  (usually  about  the  size  of  a  pinhead)  colonies 
appear  on  the  surface,  white  in  color  and  intensely  acid.  If  so, 
isolate  one,  preferably  one  that  shows  a  gas  bubble  beneath  or 
beside  it.  Inoculate  upon  an  agar  slant,  labeling  it  Bad.  aerog- 
enes(f).  Whether  it  is  really  that  species  will  be  determined  later. 
If  no  gas  bubbles  appear,  isolate  several  of  the  large,  acid,  surface 
colonies  and  some  of  them  will  probably  prove  to  be  the  species 
desired. 

In  the  same  way  isolate  and  inoculate  on  agar  slants  one  rapid 
and  one  slow  liquefier,  and  several  of  the  neutral  type  of  colonies. 

6.  Milk  Agar. — Add  1.5%  agar  to  some  skim  milk.  Af- 
ter half  an  hour  boil  (better  to  heat  in  an  autoclave)  until  the  milk 
curdles  into  a  custard.  Replace  water  of  evaporation;  adjust  re- 
Fig.  70. 


Platinum  Needles. 

action  to  1.5%  acid;  filter  through  absorbent  cotton;  place  in  tubes 
and  sterilize  in  the  usual  way.  After  the  third  sterilization  slant  the 
tubes  and  allow  to  harden.  This  milk  agar  is  not  so  transparent  as 
ordinary  agar,  but  the  lactic  bacteria  grow  upon  it  more  readily. 
7.  Oidium  Lactis. — Procure  a  little  soft  cheese  from  market, 
preferably  of  the  Camembert  or  Brie  type.*  Pour  out  into  a 
petri  dish  a  tube  of  plain  gelatin,  and  into  another  a  tube  of  lit- 
mus gelatin.  Allow  to  harden.  With  a  platinum  needle  scrape  off 
a  little  of  the  growth  on  the  rind  of  the  cheese  and  touch  it  upon 
the  surface  of  the  gelatin  at  several  spots.  It  is  well  to  try  several 
parts  of  the  cheese  rind  in  this  way.  Cover,  and  after  two  days* 
growth  it  will  usually  be  possible  to  find  spreading  colonies  of 

*  If  such  soft  cheese  is  not  to  be  found  conveniently,  oidium  lactis  can  usually  be. 
iound  in  samples  of  old  tub  butter. 


298 


CLEAN  MILK 


Oidium  on  the  plates.  They  are  thin,  and  spread  rapidly  over  the 
surface;  they  may  be  recognized  under  the  microscope  because  at 
first  they  are  seen  to  be  composed  of  threads  like  a  mold,  which 
soon  break  up  into  short  sections.  The  colonies  usually  become 
about  54  mcn  in  diameter. 

8.     Cheese  Mold. — On  the   same  plates,   after  2  or   3   clays, 
will  appear  a  white  mold.    This  grows  more  slowly  than  the  Oidium, 

Fig.  7r 


/"/■■; 


Cutter  for  Making  Potato  Plugs,  Method  of  Cutting  them  and  Placing  Them  in  Tubes. 

and  its  threads  do  not  break  up  into  spores.  Spores  form  on  the 
surface  upon  special  branches. 

Both  the  Oidium  and  mold  may  be  isolated  for  future  study 
if  time  permits. 

9.  Testing  Characters  of  Bacteria. — Inoculate  the  several 
bacteria  previously  isolated  and  purified,  into  various  media.  In 
doing  this  it  is  best  to  make  first  a  fresh  agar  slant  from  each 


LABORATORY  WORK  299 

bacterium  to  be  tested,  so  that  the  inoculation  may  be  made  from  a 
culture  not  over  24  hours  old.  Inoculate  with  a  small  amount  of  the 
growth  from  the  agar  surface,  the  following : 

a.  An  agar  slant,  b.  A  gelatin  stab.  c.  A  tube  of  plain 
bouillon,  d.  A  dextrose  fermentation  tube.  e.  A  lactose  fer- 
mentation tube.  /.  Two  milk  tubes,  one  to  be  kept  at  yo°  and 
the  other  at  98 °.  g.  Two  potato  tubes,  one  at  70 °  and  one  at 
98.  °  Allow  the  cultures  to  grow  several  days,  examining  each  day. 
For  each  species  of  bacterium  make  a  careful  record,  noting  es- 
pecially the  following  points : 

Agar  slant.     Note  the  type  of  surface  growth. 

Morphology.  Stain  and  study  with  the  microscope,  noting 
shape — formation  of  chains — spores — determine  motility. 

Gelatin  stab.  Note  liquefaction — needle  growth — surface 
growth — color.    Compare  the  growth  with  the  different  types  shown 

Fig.  72. 

i  2  3  4  5  6  1 

Types  of  Surface  Elevation. 

1.  Flat.     2.  Raised.     3.  Convex.     4.  Pulvinate.     5.  Capitate.     6.  Umbilicite. 
7.  Umbonate. 

in  figure  73,  "and  determine  with  which  each  agrees.  Note  the 
amount  of  elevation  of  the  surface  growth. 

Bouillon.     Note  turbidity — scum — sediment. 

Fermentation  tubes.     See  below  (No.  10). 

Milk  tubes.  Note  at  yo°  and  980  the  development  of  acid  as 
shown  to  litmus  paper — curdling — separation  of  whey — appearance 
of  gas  bubbles — subsequent  softening  of  the  curd,  called  digestion. 

Potato  tubes.  At  700  and  980.  Note  color  of  growth — 
abundance  of  growth — texture  of  growth — discoloration  of  potato. 

By  such  characters  as  above  determined,  different  kinds  of 
bacteria  are  distinguished  and  described.  For  a  complete  descrip- 
tion, more  characters  than  those  mentioned  are  necessary.*     For 

*  For  more   detailed  description  of  special  bacteria,  see  Conn's  "  Practical  Dairy 
Bacteriology." 


3oo  CLEAN  MILK 

characters  of  the  cultures  which  have  been  named,  Bact.  lactis  acidi 
and  Bact.  aero  genes,  see  Xo.  5. 

10.  Fermentation  Tubes. — Inoculate  a  series  of  fermen- 
tation tubes  (dextrose,  lactose  and  saccharose)  with  different  bac- 
teria. Among  those  chosen  should  be  one  culture  of  Bact.  lactis 
acidi,  and  one  of  Bact.  aerogenes.  In  two  days,  note  whether  gas 
has  been  produced  in  the  closed  arms,  and,  by  means  of  litmus  paper, 
whether  the  bouillon  has  become  acid.  If  gas  shows  in  the  fer- 
mentation tubes,  determine  the  gas  ratio  as  follows : 

Without  disturbing  the  gas,  fill  up  the  bulb  to  the  top  with 
a  2%  NaOH.  (By  a  mark,  note  the  level  of  the  gas  in  the  glass 
arm.)  Place  the  thumb  over  the  opening  in  such  a  way  that  there 
will  be  no  air  bubble  between  the  thumb  and  the  surface  of  the 
liquid.  Now  invert  the  tube,  allowing  the  gas  to  flow  out  into  the 
bulb,  and,  by  turning  back  and  forth,  mix  the  gas  with  the  NaOH 
solution  in  the  bulb,  keeping  the  thumb  very  tightly  closed  over  the 
opening.  After  thoroughly  mixing,  turn  the  tube  once  more  so  that 
all  of  the  gas  will  be  in  the  closed  arm.  Remove  the  thumb;  it  will 
usually  be  found  that  the  level  of  the  gas  in  the  closed  arm  rises. 
If  so,  it  will  be  due  to  the  fact  that  C02  has  been  dissolved  by  the 
NaOH  solution.  By  determining  the  amount  of  the  gas  before  and 
after  the  test,  the  proportion  of  C02  to  the  gases  not  thus  dissolved 
may  be  obtained.  This  is  called  the  gas  ratio.  Some  gas-producing 
species  of  bacteria  produce  large  quantities  of  carbon  dioxide,  and 
small  quantities  of  other  gases,  while  other  species  produce  no  carbon 
dioxide. 

From  one  or  two  of  the  test  tubes  inoculated  above,  that  show 
an  acidity,  determine  the  amount  of  acid  produced.  For  this  pur- 
pose remove  from  the  tube  either  5  or  10  c.c.  of  the  liquid,  dilute 
it  with  10  times  its  bulk  of  water,  heat  and  titrate. 

11.  To  Determine  Motility.  Inoculate  a  little  of  the  bac- 
teria growth  of  No.  21  into  a  test  tube  of  bouillon.  Allow  it  to 
grow  for  about  24  hours.    By  this  time  the  liquid  will  become  some- 


LABORATORY  WORK 


30  r 


what  cloudy.  Transfer  a  loopful  of  this  material  to  a  glass  slide  and 
place  upon  it  a  cover-glass.  Place  the  whole  under  a  microscope,, 
preferably  using  a  1 /6-inch  objective,  and  narrow  the  diaphragm 
below  the  stage  until  most  of  the  light  has  been  cut  off.  Now  focus 
very  carefully  upon  the  bacteria  under  the  cover-glass,  and,  if  they 
are  motile,  it  will  be  seen  that  they  are  moving  around  through  the 
microscope  field  with  more  or  less  rapidity.  If  they  are  stationary, 
it  may  be  assumed  that  they  have  no  flagella.  This  test  requires 
great  care,  for  with  some  slowly  moving  forms  it  is  not  always  easy 
to  detect  the  motion  with  certainty ;  but  it  can  easily  be  done  with  a 

little  study. 

Fig.  73- 


b  c  d 

Types  of  Gelatin  Liquefaction 
a.  Crateriform.     b.  Napiform.     c.  Infundibuliform.     d.  Saccate. 


Stratiform. 


12.  Germicidal  Action  of  Milk.  Procure  some  milk  fresh: 
from  the  cow;  dilute  1  c.c.  of  this  milk  100  times  and  make  6. 
agar  (or  gelatin)  plates.  Cool  the  rest  of  the  milk  at  once  to 
700.  At  the  end  of  2  hours  make  6  more  plates  in  exactly  the  same 
way  as  above.  In  2  hours  more  make  6  more  plates.  After  proper 
time  for  growth,  count  the  colonies  and  determine  whether  there 
has  been  a  decrease  in  numbers  of  bacteria  in  the  first  few  hours 
after  milking. 

13.  Aseptic  Milk.  Sterilize  a  liter  flask  plugged  with 
cotton.  Wash  the  hands  thoroughly  in  hot  water  and  soap,  and 
put  on  a  clean  milking  suit.  Remove  a  clean  cow  from  the  barn 
into  the  open  air,  brush  the  dirt  from  the  flanks  and  udder  with 


3o2  CLEAN  MILK 

a  clean  brush  and  then  with  a  damp  cloth.  Wash  the  udder  and 
especially  the  teats  with  a  10%  borax  solution.  After  drawing  about 
a  dozen  jets  on  to  the  ground,  remove  the  plug  from  the  flask  and, 
placing  its  mouth  very  close  to  the  teat,  milk  it  about  half  full,  and 
replace  the  cotton  plug.  Carry  at  once  to  the  laboratory  and  make 
a  litmus  gelatin  plate  immediately,  diluting  10  times.  After  2  or 
3  days'  growth,  count  the  colonies.  Are  there  any  acid  colonies 
of  the  Bad.  lactis  acidi  present?  If  time  permits,  isolate  the  col- 
onies; purify  and  determine  the  general  class  of  bacteria. 

Allow  the  rest  of  the  milk  to  stand  at  about  jo°  to  see  if  it 
will  sour  normally. 

14.  Effect  of  Temperature  on  Species  of  Bacteria  in  Milk. — 
Procure  some  fresh  milk  and  make  several  litmus  gelatin  plates, 
diluting  100  times.  Divide  the  milk  in  three  lots,  placing  one  at 
about  500,  one  at  700,  and  one  at  980.  At  the  end  of  24  hours 
make  plates  from  each,  diluting  that  kept  at  500  2,000  times,  that 
at  700  10,000  and  100,000  times,  and  that  kept  at  980  500,000 
times.  After  another  24  hours,  make  some  plates  from  the  sample 
at  700,  diluted  10,000  times.  Allow  all  plates  to  grow  at  room  tem- 
perature until  the  colonies  are  well  developed.  Determine  the  total 
number  of  bacteria  in  each  sample,  and  the  number  and  percentage 
of  each  kind  of  bacteria  that  can  be  clearly  distinguished  by  its 
colony.  Compare  the  numbers  and  percentages  of  the  different 
species  at  the  different  temperatures. 

15.  Bacteria  of  the  Air. — Place  one  dozen  tubes  of  steril- 
ized milk — with  cotton  plugs  removed — in  various  places  around 
the  barn,  dairy,  house  and  laboratory.  Leave  undisturbed  for  6 
hours.  Then  replace  the  plugs,  carry  all  to  laboratory,  and  place  at 
about  700.  "Watch  for  several  days  and  notice  whether  all  appear 
to  undergo  the  same  kind  of  fermentation.  Do  any  of  them  sour 
normally?    Do  any  remain  unchanged? 

16.  Types  of  Bacteria  from  the  Air. — After  the  tubes  in 
No.    15   show  signs  of  fermentation  make  a  gelatin  plate   from 


LABORATORY  WORK  303 

each,  using  a  loopful  of  the  milk  in  a  water  blank  and  inoculating; 
gelatin  tubes  with  a  small  loopful  of  the  water  blank  dilution. 
After  proper  growth  examine  the  colonies  in  the  different  plates 
and  compare  with  each  other.  What  does  the  experiment  teach? 
If  time  permits,  the  colonies  may  be  isolated,  purified  and  further 
studied. 

17.  Dust  Plates. — Pour  12  tubes  of  melted  gelatin  into  petri 
dishes ;  cover  and  allow  to  harden. 

a.  During  the  milking  of  a  cow  hold  one  of  the  above  gelatin 
plates  under  the  udder  of  the  cow,  close  to  the  milk  pail;  remove 
the  cover  so  as  to  allow  any  dust  particles  to  fall  on  the  gelatin,  for 
half  a  minute.     Replace  the  cover  and  carry  to  the  laboratory. 

b.  Place  3  of  the  flasks  at  different  places  in  a  cow  barn 
several  hours  after  feeding.  Remove  the  covers  for  3  minutes. 
Replace  covers  and  carry  to  laboratory. 

c.  Repeat  b  ten  minutes  after  feeding  the  cows  with  hay. 

d.  Repeat  c  after  feeding  with  other  foods. 

e.  Expose  one  plate  the  same  length  of  time  out  of  doors. 
After  the  above  plates  have  developed  count  the  colonies  on 

all  the  plates  and  compare. 

18.  Bacteria  in  Hay. — Soak  a  little  hay  in  warm  (not 
hot)  water  for  an  hour.  Shake  well  and  inoculate  three  litmus 
gelatin  tubes,  the  first  with  one,  the  second  with  two  and  the  third 
with  three  loops  full  of  the  hay  infusion.  Pour  into  petri  dishes, 
incubate  and  study  as  usual.  Compare  the  numbers  of  liquefiers 
and  non-liquefiers.    Are  there  any  acid-forming  colonies? 

19.  Bacteria  in  Grain. — Repeat  the  above  experiment,  using 
some  grain  feed  instead  of  hay. 

20.  Value  of  Cleaning  Milk  Bottles. — Procure  4  glass  bottles 
in  which  milk  has  been  standing  for  a  day;  ordinary  unwashed 
milk  bottles  are  best. 

a.  Wash  one  with  cold  water. 

b.  Wash  one  with  hot  water  and  soap. 


304  CLEAN  MILK 

c.  Wadi  the  third  and  sterilize  in  steam. 

d.  Leave  fourth  unwashed. 

Fill  all  four  with  fresh  milk.  Place  all  side  by  side  at  a  room 
temperature  and  notice  the  time  of  souring  in  each  case. 

21.  Bacteria  in  the  Milk  Pail. — Place  ioo  c.c.  of  sterile 
water  in  a  milk  pail  that  has  received  a  simple  washing.  With  a 
little  absorbent  cotton  rub  this  water  around  thoroughly;  allow  to 
stand  a  few  moments,  and,  after  another  washing  around  the  pail, 
remove  I  c.c.  of  this  water  and  plate  in  agar.    Count  the  colonies. 

a.  Repeat,  using  (i)  a  dirty  pail;  (2)  a  pail  simply  steamed 
for  a  few  seconds  in  a  steam  jet,  and  (3)  a  thoroughly  sterilized 
pail. 

22.  Bacteria  in  Manure.  With  a  sterilized  platinum  loop 
transfer  a  small  bit  of  either  fresh  or  dried  manure  from  a  cow 
to  sterile  water  flask.  Mix  thoroughly.  Transfer  two  loopfuls 
of  the  mixture  to  a  tube  of  melted  agar.  Pour  into  petri  dishes 
and  after  growth  count  the  number  of  colonies.  To  determine  the 
actual  number  in  manure  it  is  necessary  to  weigh  the  original  bit  of 
manure  and  make  subsequent  calculations. 

23.  Isolation  of  B.  Coli. — Repeat  No.  22,  using  litmus 
agar.  If  any  strong  acid  surface  colonies  appear,  choose  one  that 
shows  a  gas  bubble  if  possible;  isolate,  inoculate  on  an  agar  slant, 
and  purify  as  usual.  From  the  purified  culture  inoculate  a  glucose 
fermentation  tube.  If  gas  appears,  examine  the  culture  and  deter- 
mine whether  the  bacterium  is  a  short  motile  rod.  If  so,  the  species 
is  probably  B.  coli;  if  it  is  not  motile,  it  is  probably  B.  aero  genes. 
Compare  with  page  296,  /. 

24.  Bacteria  on  Hair. — Melt  a  tube  of  agar  and  one  of 
gelatin,  and  pour  into  petri  dishes.  After  they  have  hardened 
place  upon  the  surface  of  each  one  or  two  hairs  from  the  flank  of 
a  cow.  Two  or  three  days  later  examine,  and  note  the  numerous* 
bacterial  colonies  growing. along  the  course  of  the  hairs. 

25.  Fore  Milk. — Draw   the   first   3   jets   of  milk    from   one 


LABORATORY  WORK  305 

teat  of  a  cow  into  a  sterile  test  tube.  Now  milk  the  cow  about  one- 
half  dry  and  draw  6  more  jets  in  a  second  sterile  tube.  Remove 
to  laboratory  and  plate  at  once  in  plain  gelatin,  diluting  10  times. 
Compare  the  numbers  and  kinds  of  colonies  in  the  two  sets  of  plates. 

26.  Bacteria  on  the  Hands. — Wash  the  hands  thoroughly 
in  200  c.c.  of  sterile  water.  Place  1  c.c.  of  this  water  in  a  tube 
of  melted  agar.  Count  the  colonies  and  calculate  the  number  of 
bacteria  removed  from  the  hands  by  washing. 

27.  Estimation  of  Dirt  in  Milk* — Procure  some  milk  from 
a  clean  and  carefully  kept  dairy  and  also  some  from  a  dairy 
where  the  milking  is  done  in  a  careless,  slovenly  fashion.  Deter- 
mine the  amount  of  dirt  in  the  milk  in  each  case,  as  follows:        *», 

a.  First  method.  Place  a  quart  or  a  liter  of  each  sample  of 
milk  in  a  tall  glass  cylinder,  and  allow  it  to  stand  for  several  hours. 
A  deposit  of  dirt  will  collect  at  the  bottom,  which  may  easily  be 
seen  by  looking  through  the  glass.  With  a  siphon  carefully  re- 
move the  milk  to  within  %  inch  of  tne  bottom,  but  do  not  disturb 
the  sediment.  Fill  up  with  clean  water  and  allow  to  settle  again. 
Once  more,  after  settling,  siphon  off  the  liquid,  and  fill  the  glass' 
■with  water.  Repeat  this  operation  several  times,  until  the  water  be- 
comes fairly  clear.  Then,  after  allowing  the  material  to  settle  again, 
siphon  off  a  considerable  portion  of  the  liquid,  and  after  thoroughly 
mixing  the  sediment  with  the  remainder  of  the  water  in  the  cylinder,, 
pour  it  through  carefully  weighed  filter  paper ;  wash  the  filtrate  by 
means  of  water  through  the  filter  paper.  Remove  the  filter  paper 
and  dry,  until  it  comes  to  a  constant  weight.  Weigh.  The  differ- 
ence in  weight  between  this  and  the  original  weight  of  the  filter 
paper  will  give  the  weighed  amount  of  dirt  collected. 

b.+  Second  method.  Place  a  definite  quantity  of  milk,  usually 
10  c.c,  in  one  of  the  glass  tubes  of  a  centrifugal  machine.     Set  the 


*  This  experiment  is  impossible  without  a  chemist's  balance  and  apparatus  for  drying, 
such  as  used  in  quantitative  chemistry  and  analysis. 


3o6  CLEAN  MILK 

machine  in  motion  and  rotate  rapidly  for  ten  minutes.  By  this  time 
the  sediment  will  mostly  be  thrown  to  the  smaller  end  of  the  tube. 
The  cream  and  milk  are  then  to  be  carefully  removed  from  the  sedi- 
ment with  a  pipette,  and  the  tube  filled  up  again  with  clean  water 
and  centrifugalized  again.  This  is  to  be  repeated  until  the  water  be- 
comes clear,  after  which  the  sediment  in  the  bottom  of  the  tubes 
is  to  be  carefully  washed  out  with  clean  water  upon  a  filter,  and 
the  rest  of  the  procedure  is  as  above. 

c.  Third  method.  Procure  some  bolting  cloth  of  the  finest 
mesh.  The  meshes  should  be  fine  enough  to  retain  all  the  visible 
particles,  but  to  allow  fat  particles  to  pass  through.  Place  in  a 
ribbed  funnel,  moisten  with  water,  and  pour  through  it  cne  quart 
(or  liter)  of  milk.  Wash  the  material  left  on  the  cloth  with  water 
and  then  with  a  mixture  of  ether  and  alcohol,  equal  parts.  Wash 
the  dirt  on  to  a  carefully  weighed  filter  paper.  Dry  thoroughly  and 
weigh  as  above. 

28.  The  Covered  Milk  Pail. — Milk  two  cows,  one  into 
an  ordinary  milk  pail  with  a  flaring,  open  mouth  and  the  other  into 
a  covered  milk  pail.  Determine  the  amount  of  dirt  in  the  milk  in 
each  case.  Immediately  after  the  milking,  in  each  case,  make  a 
quantitative  count  of  the  number  of  bacteria,  comparing  the  results 
together,  and  determine  the  value  of  a  covered  milk  pail.  The  next 
day  repeat  the  experiment,  reversing  the  two  cows. 

29.  Advantage  of  Immediate  Cooling. — Immediately  after 
milking,  cool,  by  aerating,  part  of  the  milk,  and  place  in  steril- 
ized jar.  Fill  another  similar  jar  with  milk  not  cooled.  Fill  a  third 
jar  with  milk  cooled  by  immersing  at  once  in  iced  water.  Place  all 
three  jars  side  by  side  in  an  ordinary  room  and  compare  the  time 
of  souring  and  curdling  in  the  three  specimens. 

Cool  night's  milk  immediately,  as  cool  as  possible.  The  next 
morning  fill  two  jars,  one  with  the  night's  milk  that  has  been  cooled 
and  the  other  with  the  milk  warm  from  the  cow.     Place  both  at  a 


LABORATORY  WORK  307 

temperature  of  an  ordinary  room  and  compare  the  time  of  souring 
.and  curdling  in  the  two  cases. 

30.  The  Effect  of  Careful  Milking. — Compare  the  effect 
of  milking,  for  six  successive  days,  with  and  without  precautions. 
The  first  three  days  use  open  milk  pails  and  make  no  special  attempt 
at  cleanliness.  The  second  three  days  use  closed  milk  pails,  groom 
the  cows,  wash  the  udders  and  perform  the  milking  out-of-doors  in- 
stead of  in  the  closed  barn.  In  each  case  make  a  quantitative  analy- 
sis of  the  number  of  bacteria  in  the  milk  and  compare  the  results. 

31.  Sterilization  by  Boiling. — Make  a  set  of  bacterial 
plates  from  a  sample  of  milk  gelatin.  Then  boil  the  milk  for  five 
minutes  in  a  flask  closed  with  cotton  and  make  another  set  of 
plates,  diluting  by  10.  Allow  the  boiled  milk  to  stand  for  24  hours 
and  make  another  set  of  bacterial  plates,  diluting  by  100.  Allow 
the  rest  of  the  boiled  milk  to  stand  in  the  laboratory  until  it  shows 
signs  of  fermentation.  Determine  whether  it  has  soured,  and  de- 
scribe any  other  notable  change.  After  the  plates  have  had  an  op- 
portunity to  grow,  count  the  number  of  bacteria. 

32.  Pasteurizing  Milk. — Obtain  some  milk  that  is  from 
12  to  20  hours  old.  Make  a  set  of  plates  on  agar,  diluting  by  1,000. 
Divide  the  milk  into  two  lots.  Heat  one  lot  to  a  temperature  of 
1400  for  one-half  hour,  stirring  frequently.  Heat  the  other  lot 
to  1600  for  10  minutes.  Allow  both  to  cool  and  make  agar  plates 
from  each,  diluting  by  100.  After  plates  have  grown,  calculate  the 
number  of  bacteria  before  and  after  pasteurizing  at  the  different 
temperatures. 

a.  Repeat  the  last  experiment,  making  plates,  however,  in  lit- 
mus gelatin  and  calculating  the  number  and  percentage  of  acid 
colonies  in  the  milk  before  and  after  pasteurizing. 

33.  Quantitative  Analysis  of  Miscellaneous  Milk  Samples. 
— Obtain  milk  samples  from  several  milkmen,  learning,  so  far 
as  possible,  the  age  of  each  sample  of  milk.  These  should  be  col- 
lected in  sterile  bottles  and  kept  on  ice  until  they  can  be  experimented 


,308 


CLEAN  MILK 


with  in  the  laboratory.  Dilute  each  sample  of  milk  1,000  times  and1 
make  agar  plates  from  the  final  dilution;  incubate  at  98°.  After 
24  hours  count  the  number  of  bacteria  in  each  plate  and  compare 
the  samples  of  milk. 

34.     Qualitative  Analysis  of  Miscellaneous  Milk  Samples — 
With  the  specimens  above  collected  it  will  be  useful  to  attempt  a 
qualitative  analysis,  though  this  will  be  more  difficult.     The  dilu- 
tion of  the  milk  must  be  varied  according  to  its  age  and  temper- 
Fig.  74- 


12. 


m 


Flasks  and  vials  for  quantitative  bacteriological  analysis. 

ature.  If  it  is  fairly  fresh — only  a  few  hours  old — a  dilution  of  a 
thousand  times  is  satisfactory.  If  it  is  12  hours  old,  a  dilution 
should  be,  at  least,  10,000;  and  if  24  hours  old,  it  should  be  as  high 
as  100,000,  or  higher.  The  amount  of  dilution  necessary  may  be 
determined  by  a  direct  microscopic  study.  Make  and  stain  a  slide 
from  each  sample  of  milk,  as  directed  in  No.  3.  Count  the  number 
of  bacteria  per  field.  If  the  average  number  per  field  is  less  than 
10,  dilute  the  milk  100  times.  If  it  is  as  high  as  100,  dilute  1,00a 
times;  and  if  still  higher,  dilute  in  the  same  proportion. 


LABORATORY  WORK  309 

After  diluting  the  milk  make  six  litmus  gelatin  plates  from 
'each  sample.  It  is  best  to  have  three  of  these  plates  diluted  twice 
as  highly  as  the  other  three.  After  cooling,  place  at  a  temperature 
of  700.  After  two  days,  examine  and  determine  whether  there  are 
any  rapidly  liquefying  colonies  that  are  likely  to  destroy  the  plates ; 
if  so,  make  a  study  of  the  plates  at  once.  If  possible,  however,  keep 
the  plates  for  four  days  before  studying  them. 

Study  of  plates. — After  the  plates  have  grown  (2  to  4  days),: 
study  as  follows : 

a.  Determine  total  number  of  bacteria  per  c.c.  of  milk.  Com- 
pare  with  the  total  number  found  on  the  agar  plates. 

b.  Determine  the  number  of  liquefying  colonies. 

c.  Determine  the  number  of  acid  bdetcria  per  c.c.  Are  they 
of  the  Bad.  ladis  acidi  type  ? 

d:  Calculate  the  percentage  of  acid  bacteria — liquefiers  and 
miscellaneous  bacteria  in  the  milk.  Draw  a  conclusion  as  to  which 
samples  were  probably  badly  contaminated. 

35.  Bacteria  in  Fresh  Cream. — Dilute  one  c.c.  of  freshly 
separated  cream  with  sterile  water.  If  this  is  separated  by  a  sep- 
arator, the  dilution  should  be  about  1,000.  If  the  cream  has  been 
separated  by  the  gravity  method,  the  dilution  should  be  higher, 
since  the  cream  is  older,  and  should  be  as  high  as  100,000.  After 
diluting,  make  a  series  of  four  plates  in  litmus  gelatin,  incubate  at 
yo°  and  study  as  described  in  No.  56. 

36.  Bacteria  in  Ripened  Cream. — Repeat  experiment  No. 
35,  using,  however,  some  ripened  cream  that  is  just  ready  for 
churning.  In  this  case  the  dilution  must  be  much  higher,  and 
probably  never  less  than  1,000,000.  After  incubating,  determine 
the  variety  and  numbers  of  bacteria  present. 

37.  Analysis  of  Butter  Milk. — Make  an  analysis  of  the 
bacteria  in  butter  milk  in  litmus  gelatin.     The  dilution  in  this  case 

.should  not  be  less  than  100,000. 

38.  Analysis  of  Butter. — Weigh  out   upon  accurate  chem- 


310  CLEAN  MILK 

ical  scales  5  grams  of  freshly  made  butter.  Place  this  in  a  sterile 
mortar,  with  9.5  c.c.  of  sterile  water.  Rub  the  water  and  the 
butter  together  thoroughly,  so  as  to  distribute  the  bacteria  as  uni- 
formly as  possible  through  the  water.  This  mixing  should  be  con- 
tinued for  some  time,  for,  at  best,  many  of  the  bacteria  will  remain 
clinging  to  the  fat.  Dilute  this  mixture  10,000  times  and  make  a 
series  of  agar  or  litmus  gelatin  plates.  Incubate  and  count  as  usual. 
After  24  hours  make  a  second  series  of  plates  from  the  same 
sample  of  butter,  and  repeat  again  in  two  days  and  one  week.  Ob- 
tain, if  possible,  a  sample  of  butter  several  months  old,  and  make 
similar  analysis.  In  all  cases  determine  the  numbers,  and,  if  pos- 
sible, the  proportion  of  acid  bacteria  and  the  liquefiers. 

39.  Home  Starters. — Obtain  some  clean  milk  from  a  thor- 
oughly healthy  cow ;  place  in  sterile  vessels,  and  cover  to  keep 
out  the  dust.  Set  aside  at  about  65 °  until  the  milk  is  soured  but 
not  quite  curdled.  Examine  carefully  by  taste,  by  smell  and  by 
general  appearance,  to  determine  whether  the  curd  seems  to  be  of  a 
type  favorable  for  butter-making.  It  should  be  smooth  in  appear- 
ance, and  have  a  clean,  sharp  taste  and  pleasant  odor.  Use  this, 
if  convenient,  as  a  starter  for  ripening  cream. 

40.  Making  a  Starter  from  a  Commercial  Culture. — Ster- 
ilize a  quart  of  milk  by  boiling  half  an  hour,  or  half  an  hour  in  an 
autoclave  at  10  pounds  pressure.  After  cooling  to  about  8oD,  pour 
into  it  the  contents  of  a  package  of  commercial  butter  starter,  stir 
thoroughly,  cover  and  allow  to  stand  at  65°  to  yo°  for  24  hours. 
The  milk  should  by  this  time  be  sour  and  nearly  ready  to  curdle, 
and  may  be  used  at  once  as  a  starter.  If  a  larger  amount  is  needed, 
pasteurize  several  gallons  of  cream  by  heating  to  155^  for  one  half 
hour.  Cool  to  8o°,  and  pour  into  it  the  quart  of  starter  prepared 
from  the  commercial  culture.  Allow  to  stand  at  65  °,  after  which  it 
is  ready  for  use. 

41.  Bacteriological  Analysis  of  a  Commercial  Culture. — 
Make  a  bacteriological  analysis  of  some  commercial  culture  to  de- 


LABORATORY  WORK  311 

termine  whether  it  is  pure  or  not.  For  this  purpose  put  a  small 
quantity  of  the  culture  from  the  package  into  a  water  blank,  and, 
by  thorough  agitation,  distribute  evenly  through  the  water.  From 
this  inoculate  litmus  gelatin  tubes,  some  with  one,  some  with  two 
and  some  with  three  loopfuls  of  the  diluted  culture.  Pour  into 
petri  dishes,  incubate  at  700,  and  after  three  days  examine  to  see 
whether  any  bacteria  can  be  found  in  the  plate  except  lactic  germs. 

42.  Effect  Upon  Butter  of  Pasteurizing  Cream. — Divide 
a  lot  of  cream  which  is  to  be  made  into  butter  into  two  parts,  pas- 
teurize one  at  a  temperature  of  1550  for  15  minutes,  leaving  the 
other  without  pasteurization.  Add  to  each  the  same  amount  of 
starter.  Ripen  in  the  usual  way,  churn  and  make  into  butter,  and 
compare  the  products,  to  see  if  any  difference  can  be  noted  between 
the  butter  from  pasteurized  and  non-pasteurized  cream. 

43.  The  Effect  of  Light  Upon  Butter. — Place  two  lots  of 
butter,  one  in  a  bright  light  and  one  in  the  dark,  and  after  several 
days  compare  them  as  to  appearance,  smell  and  taste. 

44.  Ripening  of  Cream  at  Different  Temperatures. — Divide 
some  cream  into  three  lots.  Place  the  usual  amount  of  starter 
in  the  cream,  and  ripen  one  lot  at  500,  one  at  65  °  and  one  at  85  °. 
After  proper  ripeness  has  been  reached  (determined  by  acid  test), 
churn  and  compare  the  butter  which  is  obtained,  unsalted,  to  detect 
any  difference  in  flavor  and  aroma. 

45.  Analysis  of  Bacteria  in  Cheese. — Determine  the  number 
of  bacteria  in  cheese  exactly  as  above  described  for  butter  (see 
experiment  38,),  making  inoculation  into  litmus  gelatin  plates,  and 
determine  the  varieties  of  bacteria  present.  Make  a  series  of  plates 
in  this  way  from  a  freshly  made  cheese  and  another  series  from 
some  cheese  ripened  and  ready  for  market.  Compare  the  numbers 
and  kinds  of  bacteria. 

46.  Effect  of  Different  Species  of  Bacteria  on  Milk. — In- 
oculate a  series  of  sterile  milk  tubes  with  a  large  number  of  different 
kinds  of  bacteria.    It  is  well  for  this  purpose  to  use  all  of  the  species 


3i2  CLEAN  MILK 

isolated  during  these  experiments,  and  as  many  other  kinds  of 
bacteria  as  may  be  available.  Set  all  of  the  tubes  aside  at  JO° ,  and 
at  intervals  of  24  hours  examine  each  to  determine  the  effect  upon 
the  milk  of  the  different  species  of  bacteria.  The  acidity  should  be 
tested  by  removing  a  loopful  and  placing  on  litmus  paper,  and  special 
attention  should  be  given  to  curdling,  separation  of  whey,  appear- 
ance of  gas  bubbles,  the  digestion  of  the  curd  and  the  appearance  of 
odors  as  a  result  of  the  action  of  the  different  bacteria.  The  larger 
the  variety  of  the  different  cultures  used,  the  better. 


APPENDIX 


Dairy  Cows 

THE  writer  has  not  said  anything  about  the  best  kind  of  cow  for 
producing  clean  milk,  because  it  is  as  impossible  to  affirm  posi- 
tively which  is  the  best  breed  of  dairy  cows  as  it  would  be  to 
state  which  is  the  best  race  of  human  beings.  Each  breed  has  its  own 
valuable  characteristics  which  are  in  accord  or  otherwise  with  the 
views  of  different  cattle  owners,  depending  on  the  experience,  tempera- 
ment or  characteristics  of  the  owner. 

The  dairy  breeds  of  chief  importance  are  four :  The  Jerseys, 
Guernseys,  Holsteins  and  Ayrshires.  The  Brown  Swiss  and  Short 
Horn  are  called  dual  purpose  cows  ;  that  is,  useful  for  milk  and  beef. 
For  dairy  purposes  alone  they  are  inferior  to  the  first  four  breeds  men- 
tioned, however. 

The  milk  of  the  Jerseys  and  Guernseys  is  rich  in  fat,  DUt  moder- 
ate in  amount  (the  Guernsey  milk  of  especially  deep  yellow  color)  ; 
the  Holsteins  are  large  milkers,  but  the  percentage  of  fat  in  their  milk 
is  low ;  while  the  Ayrshires  occupy  an  intermediate  position — in 
respect  to  quantity  and  richness  of  their  milk — as  compared  with  the 
Jerseys  and  Holsteins.  The  milk  of  Jerseys  and  Guernseys  is  said  to 
be  not  quite  so  digestible  for  infants,  perhaps  on  account  of  its  larger 
fat  globules.  This  is  apparently  without  true  basis,  however,  since 
the  fat  globules  in  human  milk  are  larger  than  those  in  milk  of  any 
breed  of  cows  (see  p.  45).  If  milk  is  fed  undiluted  to  babies  under 
nine  months,  Jersey  and  Guernsey  milk  is  undoubtedly  too  rich.  If 
this  method  of  feeding  is  adopted,  milk  containing  3.5  per  cent,  fat  or 
less  must  be  used.  The  milk  is  said  to  vary  more  in  composition,  in  case 
of  the  pure  bred  Jerse3Ts  (on  account  of  their  excitable  temperaments), 
and  these  animals  are  possibly  more  prone  to  tuberculosis.  Clean  Jersey 
or  Guernsey  milk  is,  however,  infinitely  preferable  to  the  ordinary  dirty 
market  milk  of  any  other  breed  of  cows,  and  the  writer  has  found 
that  clean  milk  from  grade  Jersey  cows  (containing  5  per  cent,  fat) 
will  agree  perfectly  with  infants,  providing  that  it  is  diluted  properly 
in   accordance  with  its  fat  content,  see  p.  170.     The  average  consumer 

313 


3T4 


CLEAN  MILK 


of  milk  places  much  more  importance  on  the  richness  of  milk  than 
any  other  quality.  He  can  easily  see  and  appreciate  this  quality,  and 
the  cleanliness  of  the  milk  he  can  not  judge  of — except  to  notice  that 
it  keeps  well.  Moreover,  the  average  consumer  buys  the  milk  largely 
for  the  cream,  which  is  commonly  used  for  the  breakfast  cereal  and 
coffee.  For  this  reason  a  rich  milk  should  bring  the  largest  price, 
providing  that  it  is  clean. 

A  Holstein  or  Ayrshire  milk — or  a  clean  milk  obtained  from  cows 
of  various  breeds — may  be  sold  for  infants,  and  a  5  per  cent.  Jersey  or 
Guernsey  milk  may  be  sold  for  general  consumption  at  a  little  higher 
figure. 

If  the  whole  milk  is  drunk  by  adults  its  richness  is  considered  its 
most  valuable  quality.  In  Boston  a  milk  containing  6  per  cent,  of 
fat — which  m.z.y  be  obtained  from  some  Jerseys  and  Guernseys — is 
sold  for  16  cents  a  quart,  and  is  especially  intended  for  invalids.  It 
is  not  unusual  to  separate  the  milk  from  different  breeds  on  the  farm 
and  charge  different  prices  for  their  milk.  Milk  intended  for  babies 
may  appropriately  contain  about  4  per  cent,  of  fat,  and  must  be  of 
special  cleanliness  and  freshness.  Rapid  delivery  of  it  is  therefore 
necessary,  which  may  require  a  special  express  rate  on  train  and 
special  wagon  in  the  city.  The  bottles  should  be  thoroughly  pro- 
tected from  dust  by  an  outer  cap  of  parchment,  or  tinfoil,  over  the 
ordinary  paper  cap.  A  milk  for  infants  should  constantly  contain 
nearly  the  same  quantity  of  fat,  so  as  to  give  rise  to  a  cream  of  uni- 
form composition.  This  is  essential  for  the  physician  to  calculate  the 
fat  in  the  different  layers  of  cream  (see  p.  170),  and  such  milk  may  be 
supplied  if  it  is  obtained  from  one  breed  of  cows.  For  all  these  rea- 
sons the  price  of  milk  for  infant  feeding  must  be  considerable — gener- 
ally 15  cents  a  quart  retail.  A  five  per  cent,  milk  from  Jerseys 
or  Guernseys  (not  quite  up  to  the  certified  standard  for  babies) 
may  be  sold  for  general  household  use  for  from  10  to  12  cents  a 
quart. 

To  give  the  reader  an  idea  of  representative  cows  of  the  dairy 
breeds  we  have  included  an  account  of  a  Guernsey,  which  heads  the 
list  of  officially  tested  cows  (taken  from  Hoard's  Dairyman),  and  also 
tables  showing  the  records  of  a  trial — at  the  St.  Louis  Fair  of  1905 — 
of  Brown  Swiss,  Holsteins,   Jerseys  and  Short  Horns.     The  accom- 


DAIRY  COWS 


3*5 


panying  illustrations  are  of  the  best  Jersey  (Xoretta  D.)  and  the  best 
Holstein  (Shadybrook  Gerben),  at  the  Exposition,  and  of  Yeksa  Sun- 
beam (Guernsey),  and  Pansy  of  Woodroffe  (Ayrshire). 

A  Wisconsin  Guernsey. — Mr.  Rietbrock's  Yeksa  Sunbeam  (Plate 
I,  Fig.  45)  heads  the  list  of  officially  tested  cows.  Her  record  for 
twelve  consecutive  months  is  14,920.8  lbs.  milk,  and  857.15  lbs.  fat, 
and  is  as  follows  : 

Month.  Milk. 

October 1428.2 

November 1322.5 

December 1294.4 

January  '05  1217.0 

February 1060.8 

March 1185.1 

April 1089.6 

May 1127.5 

June 1158.4 

July  1266.0 

August 1463.8 

September 1307.5 

Yeksa  Sunbeam,  having  given  14920.8  lbs.  of  milk,  containing 
857.15  lbs.  fat,  it  follows  that  the  average  per  cent,  of  fat  in  her  milk 
•was  5.744.  Applying  the  Farrington  scale  to  this  quality  of  milk, 
we  find  that  100  lbs.  of  fat  should  yield  nS}(  lbs.  of  butter, 
and  consequently  the  857.15  lbs.  of  fat  would  make  1013.56  lbs.  of 
butter. 

Yeksa  Sunbeam  was  9%  years  old  at  the  commencement  of  the 
test.  She  was  bred  and  reared  by  the  late  W.  D.  Richardson,  at 
Garden  City,  Minn.,  and  sold  when  a  heifer  to  a  milkman  near  Minne- 
apolis, from  whom  she  was  purchased  by  Mr.  Rietbrock.  Her  sire 
was  Yeksa's  Prince,  a  son  of  the  cow,  Yeksa,  formerly  owned  by  Mr, 
I.  J.  Clapp,  Kenosha,  Wis.,  and  her  dam  was  The  Sunbeam,  also 
formerly  owned  in  Wisconsin  by  Prof.  Haecker,  before  he  went  to 
Minnesota.  There  is,  therefore,  some  poetic  justice  in  her  return  to 
Wisconsin  to  make  her  phenomenal  record. 

In  respect  of  feeding,  I  would  say  that  during  grazing  season,  the 
pastures  of  clover  and  blue  grass  were  very  good.     We  supplemented 


er  cent. 

fat. 

Lbs.  fat. 

Total  fat. 

5-69 

81.26 

— 

5 

62 

74-32 

I55-58 

6 

08 

73-7o 

234 

28 

6 

04 

73-51 

307 

79 

5 

75 

61.00 

36S 

79 

6 

05 

71.70 

440 

49 

5 

79 

63.09 

503 

58 

5 

75 

64.83 

568 

4i 

5 

25 

60.  S2 

629 

23 

5 

88 

74-44 

703 

67 

5 

42 

79-34 

783 

01 

5 

67 

74.14 

857 

15 

3Y6  CLEAN  MILK 

this,  during  the  fore  part  of  last  summer,  with  some  clover  hay  fed  in 
the  barn,  since  the  grass  was  very  washy  in  the  early  part  of  the  sea- 
son on  account  of  so  much  rain.  During  July  and  August  we  added 
to  the  pasturage  a  soiling  ration  of  peas  and  oats,  the  peas  being  in  a 
green  state,  the  kernel  formed  in  the  pod,  but  not  yet  ripened,  and  fed 
it  up  to  the  time  when  the  pea  was  quite  hard,  but  will  say  that  it  was 
mostly  during  the  period  that  we  would  call  peas  good  to  eat  on  the 
table  as  green  peas. 

In  August  and  September,  we  also  fed  some  green  corn  stalks.  I 
cannot  call  it  green  corn,  because  there  were  no  ears  formed  on  it. 
It  was  from  a  planting  made,  about  the  20th  of  June  and  close 
together. 

During  the  late  fall  and  winter  of  1904,  we  also  fed  Yeksa  Sun- 
beam, and  some  other  cows,  from  5  to  10  pounds  of  rutabagas.  The 
roughage  during  the  winter  season  was  mostly  clover  hay.  We  fed 
also  some  alfalfa.  I  had  16  tons,  and  this  was  consumed  by  the 
calves,  10  to  12  in  number,  the  16  cows  in  the  test  and  about  the  same 
number  of  other  cows  not  being  tested  (the  test  cows  got  a  larger 
allowance  of  alfalfa  than  the  others). 

During  the  winter,  we  also  fed  Yeksa  Sunbeam  from  25  to  30 
pounds  of  silage.  This  silage  had  very  little  grain  in  it,  since  our 
corn  did  not  mature  very  well  last  year,  but  it  was  succulent,  good 
ieed. 

Now,  as  regards  grain  ration,  we  made  a  grain  mixture  composed 
of  four  parts  wheat  bran,  two  parts  ground  oats,  two  parts  Buffalo 
gluten  feed,  one  part  Old  Process  oil  meal.  During  part  of  the  year 
we  fed  this  oil  meal  in  pea  size — little  kernels  big  as  a  pea.  During 
the  months  of  January,  February  and  March,  we  added  to  this  grain 
mixture  one  part  of  corn  meal. 

Of  the  above  grain  mixture,  we  fed  Yeksa  Sunbeam,  during  the 
months  of  October,  November  and  December,  15  pounds  a  da}T.  We 
reduced  this  by  about  1  lb.,  feeding  14  lbs.  a  day,  during  January, 
February,  March  and  April.  For  the  month  of  May,  we  reduced  her 
feed  to  12  lbs.  of  the  mixture  and,  as  we  got  her  on  to  the  grass,  and 
the  grass  improved  in  June,  I  think  we  reduced  it  still  more.  I  find 
that  a  report  has  been  made  that  she  was  fed  only  6  lbs.  of  grain  a  day 
during  June.     I  think   9  or   10  lbs.  would  be  more  nearly  cor^cU 


Fig.  75._ Yeksa  Sunbeam  (Guernsey),  No.  15,439.  Adv-  ReS-  331- 


Helendale  Stock  Farm,  Athens,  Wis.     (Fred.  Riethock,  Milwaukee,  Wis.) 
Fig.  76. — Shady  brook  Gerben  (Holstein). 


Jn  120  days  produced  8101.7  lbs.  milk  ;  test  3.5  per  cent,  fat ;  butter  fat  282,6  J  J 
butter,  330.36  lbs.;  weight,  1319  lbs. 


Fig-  77- — Pansy  of  Woodroffe  (Ayrshire),  No.  18,915. 


Champion  at  National  Dairy  Show,  Chicago.     (Property  of  Geo.  Win.  Ballou, 
Middleton,  N.  Y.) 


Fig.  7S.— Loretta  D.  (Jersey). 


DAIRY  COWS 


\T 


During  July,  August  and  September  of  this  year,  she  was  fed  daily  a 
grain  ration  of  the  above  mixture  of  9  to  10  lbs.  All  these  grain 
rations  were  fed  in  three  meals,  morning,  noon  and  night. 


RECORD   OF   THE   BEST,    POOREST   AND   AVERAGE 
I20   DAYS   AT   ST.    LOUIS   FA 

Brown  Swiss.  Holstein. 

Milk  per  day,  lbs.— 

Bestcow No.  1-51.0        No.  20-67.5 

Poorest  cow No.  3-3S.5        No.    7-47.1 

Average  cow  . . .              44 . 2  53 . 4 

Test  of  Milk- 
Best  cow 3.4  3.5 

Poorest  cow 3.8  3.2 

Average  cow. ..                3.62  3.43 

Butter  fat  per  day,  lbs. — 

Bestcow 1.748  2.355 

Poorest  cow 1-477  i-5°7 

Average  cow...                1-596  1.832 

Butter  per  day,  lbs.— 

Bestcow 2.042  2.753 

Poorest  cow i-73i  I-755 

Average  cow...               1.870  2.12 

Solids-not-fat  per  day,  lbs. — 

Bestcow 4.363  5. 171 

Poorest  cow 3.585  3614 

Average  cow .. .               3919  4-239 

Feed  cost  of  milk,  per  qt.f — 

Bestcow .0109  .0090 

Poorest  cow. . . .                  .0139  .0122 

Average  cow...                  .0124  .0107 

Feed  cost  of  butter,  per  lb. — 

Bestcow .136  .110 

Poorest  cow .155  .  164 

Average  cow. . .                 .147  -^S 
No.  of  cows   in 

herd  5  15 


COW   IN   EACH   HERD   FOR     THE 

IR,    I905.* 

Jersey. 

Ihorthorn. 

No.  37-43.4 

No. 

63- 

-43-4 

No.  36-38.8 

No. 

G2- 

-21.4 

4i-5 

34-6 

4.8 

4.0 

4.1 

3-9 

4-7 

3-3 

2-334 

1-737 

1. 615 

0.843 

I-936 

1.277 

2.750 

2.037 

1.898 

0.988 

2.28 

J -495 

4-357 

3-720 

3-441 

1.902 

3-634 

2.980 

.0110 

.0109 

.0130 

.0215 

.0116 

.0132' 

.097 

.117 

.132 

•234 

.105 

•153 

25 


28 


♦Illustrations  and  tables  of  records  and  rations  from  Daity   Cow  Demonstration,  at 
Louisiana  Purchase  Exposition,  1905.     Edited  by  Prof.  E.  H.  Fujt-ington. 
+  Assuming  two  pounds  to  the  quart. 


3i8  CLEAN  MILK 

ONE   DAY'S    RATION    OF   ONE   COW   IN    EACH    HERD   AT   ST 

Brown 
Feed  in  Pounds.  Swiss. 

Alfalfa  hay 7 

Cut  alfalfa  hay — 

Corn  silage — 

Green  cut  corn 40 

Green  cow  peas — 

Wheat  bran — 

Linseed  (oil  meal) — 

Ground  oats — 

Hominy  feed 8 

Gluten  feed — 

Corn  meal — 

Corn  hearts — 

Cottonseed  meal 1 

Distiller's  grains — 

Union  grains 15 

Total 71 

Including  grain 24 

Such  records  as  these  are  probably  a  revelation  to  many  a  man 
who  has  fed  and  milked  cows  for  years.  It  is  not  customary  to  give 
more  than  five  to  ten  pounds  of  grain  per  day  to  cows  on  the  home 
farms,  and  the  majority  of  them  probably  get  less  than  five  pounds. 
A  capacity  for  assimilating  large  rations  is  necessary  for  producing 
large  quantities  of  milk  and  butter,  and  most  of  these  World's  Fair 
cows  were  fed  to  their  limit  of  endurance.  A  daily  feeding  per  cow 
of  near  twenty  pounds  of  grain,  together  with  thirty  to  sixty  pounds 
of  green  feed,  was  not  uncommon,  although  there  were  some  varia- 
tions in  the  total  amount  during  the  120  days  of  the  test. 

Dehorning    Calves 

It  is  now  generally  recognized  that  all  milch  cows  should  be 
dehorned,  to  prevent  injury  to  themselves  (in  tearing  off  a  horn,  etc.), 
to  other  animals,  to  stables  and  to  persons.  As  the  operation  of 
removing  the  horns  from  grown  animals  is  unpleasant,  and  detri- 
mental for  the  time   to  the   patient,  the  following  simple  method, 


iRD   AT   ST. 

LOUIS   FAIR 

,    I9°5- 

Holstein. 

Jersey. 

Shorthorn. 

- 

18 

9 

15 

6 

— 

— 

16 

24 

15 

— 

— 

35 

— 

— 

2 

3 

4 

— 

2 

2 

— 

2-5 

2 

5 

2.5 

3 

— 

5-o 

2 

— 

1-5 

— 

— 

2.5 

2 

1 

— 

2 
4 

14 

- 

87 

59 

54 

22 

19 

21 

MAN  A  GEMENT  OF  HAND  SEPARA  TORS  3 1 9 

recommended  by  the  English  Board  of  Agriculture  and  found  success- 
ful in  practice,  should  be  followed  in  the  treatment  of  calves  : 

"  Clip  the  hair  from  the  top  of  the  horn,  when  the  calf  is  from 
two  to  five  days  old  ;  slightly  moisten  the  end  of  a  stick  of  caustic 
potash  and  rub  the  tip  of  each  horn  firmly  for  about  one-quarter  of  a 
minute,  or  until  a  slight  impression  has  been  made  on  the  centre  of 
the  horn.  Repeat  this  two  to  four  times  at  intervals  of  five  minutes. 
If  a  little  blood  appears  in  the  centre  of  the  horn,  after  one  or  more 
applications,  only  one  more  slight  rubbing  with  the  potash  will  be 
necessary. 

' '  The  operation  should  not  be  performed  on  a  calf  over  nine  days 
old.  Caustic  potash  can  be  obtained  from  any  druggist  in  the  form  of 
a  white  stick  (about  as  large  as  a  pencil),  and  when  not  in  use  should 
be  kept  in  a  glass  stoppered  bottle  in  a  dry  place.  One  man  should 
hold  the  calf  while  another  uses  the  caustic.  Roll  a  piece  of  tinfoil  or 
paper  about  the  end  of  the  stick  of  caustic  to  protect  the  fingers  of  the 
operator  from  contact  with  it.  Do  not  moisten  the  stick  too  much  or 
the  caustic  will  spread  around  the  horn  and  destroy  the  flesh.  For 
the  same  reason  prevent  the  calf  from  wetting  its  head  for  several 
days  after  the  operation.  Be  careful  to  rub  the  caustic  on  the  centre 
of  the  horn  and  not  around  it.  Caustic  potash  is  a  poison  and  must 
be  kept  in  a  safe  place." 

Management  of  Hand  Separators 

There  is  no  higher  authority  on  dairy  matters  than  Prof.  E.  H. 
Farrington,  of  the  University  of '  Wisconsin  Experiment  Station,  to 
whom  we  have  had  the  pleasure  of  referring  on  several  occasions  in 
the  previous  pages.  I  can  not  do  better  than  to  quote  the  rules  laid 
down  by  him  for  the  management  of  hand  separators. 

1.  Place  the  separator  on  a  firm  foundation  in  a  clean,  well-ventilated  room 
where  it  is  free  from  all  offensive  odors. 

2.  Thoroughly  clean  the  separator  after  each  skimming  ;  the  bowl  should  be 
taken  apart  and  washed,  together  with  all  the  tinware,  every  time  the  separator 
is  used  ;  if  allowed  to  stand  for  even  one  hour  without  cleaning  there  is  danger 
of  contaminating  the  next  lot  of  cream  from  the  sour  bowl.  This  applies  to  alL 
kinds  of  cream  separators. 

3.  Wash  the  separator  bowl  and  all  tinware  with  cold  water  and  then  with 
warm  water,  using  a  brush  to  polish  the  surface  and  clean  out  the  seams  and 


320  CLEAN  MILK 

cracks  ;  finally  scald  with  boiling  water,  leaving  the  parts  of  the  bowl  and  tinware 
to  dry  in  some  place  where  they  will  be  protected  from  dust.  Do  not  wipe  the 
bowl  and  tinware  with  a  cloth  or  drying  towel ;  heat  them  so  hot  with  steam  or 
boiling  water  that  wiping  is  unnecessary. 

4.  Rinse  the  milk  receiving  can  and  separator  bowl  with  a  quart  or  two  of 
hot  water  just  before  running  milk  into  the  separator. 

5.  Cool  the  cream  as  it  comes  from  the  separator,  or  immediately  after,  to  a 
temperature  near  500  F.  and  keep  it  cold  until  delivered. 

6.  Never  mix  warm  and  cold  cream  or  sweet  and  slightly  tainted  cream. 

7.  Provide  a  covered  and  clean  water  tank  for  holding  the  cream  cans  and 
change  the  water  frequently  in  the  tank  so  that  the  temperature  does  not  rise 
above  6o°  F.  A  satisfactory  arrangement  may  be  made  by  allowing  running 
water  to  flow  through  the  cream  tank  to  the  stock  watering  tank. 

S.  Skim  the  milk  immediately  after  each  milking,  as  it  is  more  work  to  save 
the  milk  and  separate  once  a  day,  and  less  satisfactory,  than  skimming  while  the 
milk  is  warm,  since  the  milk  must  be  heated  again  when  saved  until  another 
milking. 

9.  A  rich  cream,  testing  35  per  cent,  fat  or  more,  is  the  most  satisfactory  to 
both  farmer  and  factory.  The  best  separators  will  skim  a  rich  cream  as  efficiently 
as  a  thin  cream  and  more  skim  milk  is  left  on  the  farm  when  a  rich  cream  is  sold. 

10.  Cream  should  be  perfectly  sweet,  containing  no  lumps  or  clots  when 
sampled  and  delivered  to  the  haulers  or  parties  buying  it. 

There  is  a  good  demand  for  sweet  cream  and  a  perfectly  clean,  sweet  and 
satisfactory  cream  can  easily  be  supplied  either  to  a  retailer,  an  ice  cream  maker, 
or  a  creamery  by  keeping  clean  the  separator,  tinware,  strainer-cloth  and  water 
tank,  and  the  cream  cold. 

To  Keep  Records  of  Individual  Cows. 

Printed  forms  for  making  records*  should  be  used.  These  con- 
sist of  single  sheets  of  stiff  paper  which  are  ruled  so  as  to  permit  of 
keeping  a  record  of  the  night's  and  morning's  milk  in  pounds  and 
ounces  for  one  month,  and  also  supply  space  to  note  the  average  per 
cent,  of  butter  fat,  if  taken  once  or  twice  a  month.  One  sheet  may 
be  used  for  10  or  20  to  30  cows  according  to  the  size  ordered. 

Each  cow  must  be  named  or  numbered  to  use  these  sheets.  The 
metal  tags  for  insertion  in  the  cow's  ear  are  most  suitable  for  num- 
bering. As  soon  as  each  cow  is  milked  the  milk  is  poured  in  a  special 
weighing  pail  and  the  weight  is  then  recorded  on  the  milk  sheet.  A 
.spring  scale  sold  for  the  purpose  is  most  convenient.  This  is  arranged 
so  as  to  allow  for  the  weight  of  the  weighing  pail  in  order  that  it  will, 
not  have  to  be  subtracted  from  the  total  weight  of  pail  and  milk  at 
each  weighing. 


*  Printed  forms  for  keeping  cow  records  are  sold  very  cheaply  by  Hoard's  Dairyman, 
Fort  Atkinson,  Wis. 


VALUE  OF  COWS  321 

The  milk  is  poured  back  from  the  weighing  pail  into  the  mill; 
pail,  to  mix  it  thoroughly,  and  a  tablespoonful  of  the  mixed  milk  is 
poured  into  a  half  pint  bottle  containing  one  corrosive  sublimate  tablet 
for  preserving  milk  (to  be  had  of  any  dairy  supply  company).  The 
bottle  should  be  corked  and  a  similar  sample  of  night's  and  morning  s 
milk  should  be  added  to  the  bottle  for  three  days  to  one  week,  the  bottle 
being  shaken  each  time  new  samples  of  milk  are  poured  into  it.  The 
bottle  is  to  be  labelled  with  the  cow's  name  supplying  the  milk.  The 
milk  in  the  bottle  then  represents  that  from  a  number  of  milkings 
from  the  same  cow  and  is  called  a  composite  sample.  The  composite 
sample  is  tested  for  fat  by  the  Babcock  machine  (see  p.  195).  The 
night  and  morning  milk  of  each  cow  ought  to  be  weighed  and 
recorded  at  least  once  a  week  during  the  year  and  a  fat  test  made  from 
a  composite  sample  twice  a  month,  in  order  to  determine  thoroughly 
the  value  of  a  cow. 

Value  of  Cows 

I  may  be  permitted  to  submit  the  following  quotation  in  regard 
to  the  value  of  a  cow  : 

"  The  basis  of  valuation  as  set  forth  by  Prof.  S.  F.  Coolej',  of  Vt.,, 
is  that  a  cow  is  worth,  above  what  her  carcass  will  fetch,  the  sum  on- 
which  her  annual  profit  will  pay  six  per  cent,  interest,  two  per  cent, 
taxes  and  insurance,  twenty-five  per  cent,  depreciation,  or  thirty-three 
per  cent,  total. 

' '  Twenty-five  per  cent,  depreciation  means  a  sinking  fund  which 
will  pay  for  the  animal  in  four  years,  and  presupposes  the  average 
period  of  usefulness  to  be  four  years.  On  this  basis,  we  get  the  fol- 
lowing results  in  regard  to  the  values  of  cows  of  different  grades  : 

Annual  pro-      Value    of 
duct  lbs.        milk  at  $1.50        Cost  of  Value  of 

Kind  of  Cow.  milk.  per  cwt.  feed.  Profit,  cow. 

Average 3,000  $45  #45  $00  foo 

Fair 5,000  75  50  25  75 

Good 7,000  105  60  44  135 

Choice 10,000  150  75  75  225 

Pietertje  II 30,000  450  100  350  1,050 

"Asa  business  proposition,  the  difference  in  value  here  repre- 
sented appears  correct.     But  the  market  does  not  so  rate-  them.     A 


32  2  CLEAN  MILK 

poor  cow  costs  $30  and  brings  $25  in  four  years,  during  which  time 
she  sunk  $5  more  than  she  had  brought.  An  average  cow  is  worth 
what  her  carcass  will  fetch,  and  no  more.  A  fair  cow  costs  $35  to  $40 
and  -leaves  her  buyer  $50  to  the  good,  in  four  yea*.  A  good  cow 
costs  $50, -and  you  double  on  investment  the  first  year.  A  choice  cow 
costs  $75,  and  that  is  the  amount  of  her  annual  profit.  Pietertje  II 
is  worth  $1,000." ' 

- 
Plans  of  Barns  and  Milk  Rooms 

In  the  following  pages  will  be  found  illustrated  and  described  the 
stables  and  milk  rooms  of  two  farms  supplying  clean  milk  to  Seattle, 
Washington. 

The  first  farm  is  owned  by  J.  D.  Farrell,  Esq.,  and  is  not  con- 
ducted solely  for  profit  or  the  support  of  its  owner  and  may  be  regarded 
as  one  type  of  plant.  The  other  is  owned  by  \V.  H.  Paulhamus,  Esq., 
of  Sumner,  Wash.  Mr.  Paulhamus  was  the  first  to  attempt  to  supply 
Seattle  with  clean  milk  and  is  shipping  some  thousand  quarts  a  day 
from"  his  own  and  three  neighboring  farms.  His  arrangements  for 
handling  the  milk  are  therefore  adapted  to  caring  for  a  considerable 
■quantity. 

Mr.  Farrell 's stable  for  40  cows  has  a  floor,  manure  trench  and  feed- 
ing gutter  of  concrete  with  cement  finish.  The  cows  face  toward  a 
central  feeding  aisle.  Behind  the 'manure  trench  there  is  a  walk  five  feet 
wide  to  the  side  of  the  building.  The  manure  trench  is  eighteen 
inches  wide.  The  length  of 'the  stalls  is — from  the  front  edge  of  the 
manure  trench  to  that  of-  the.  feeding  gutter — six  and  one-half  feet. 
The  width  of  the  stalls  is  thifty-hihe  inches  for  some,  and  forty-three 
inches  for  .others,  to  accommodate  Jerseys  and  Holsteins.  The  feed- 
ing aisle  in  front  of  the  cattle. is  nine  feet  wide.     The  feeding  gutter 

isalso  "used  for  watering  each  time  before  feeding,  when  the  water  is 

j  .  .  .  . 

let  cut.     The  height. of  the  stable,  on  the.  sides,  is  seven  feet  four 

inches,  and  the  ceiling  is  arched  up  toward  the  centre. .   . 

;    The  .walls  and  ceiling-are -double,  with  air-space -between,  and  the 

ventilation  is  after  the  King  system.     The  cement  is  brought  up  four 

feet  on  the  walls,  and  the  rest  of  the  walls  and  the  ceiling  are  of 

matched    and  planed   boards,    tightly  fitted,   and  the    whole  painted 

white.     The  gutters 'for  manure  slope  from  six  to- ten  inches  deep  at 


PLANS   OF  BARNS  AND  MILK  ROOMS 


325 


the  lower  end,  and  drain  into  pipes  carried  a  considerable  distance  to  a 
lower  level  than  the  stable. 

Stalls. — The  rear  portion  of  each  side  of  each  stall  is  a  gate.  This 
gate  is  hinged  and  fastened  as  shown  in  plate.  The  dimensions  of  the 
gate  are  twenty-eight  inches  from  top  to  bottom,  and  forty-four  inches 
wide,  and  the  lower  edge  is  sixteen  inches  from  the  floor.  The  sta- 
tionary front  part  of  the  side  of  each  stall  is  thirty-four  inches  wide 
and  fifty  inches  high,  from  top  to  floor.  Its  lower  edge  is  ten  inches 
from  the  floor,  in  the  rear  part,  and  two  inches  above  the  gutter  for 
feeding  in  front.     The   feeding   and  watering  gutter,  of  cement,  is 

Fig.  80. 


^O    x 


Bou/ls.  (o 
Lavatory  O 

\Tub\ 


MM 


[;::,,::  ,,,,',,vti 


^= 


).:.  a  /a>,  i..  ,.v-.i       v:r->:\      \/:-".-:y\    J-'.y//w^ 


Steriliser. 


Wash  Room- 


^ 


Milk  Room 


\ 


7* 


Office. 


Shipping  7 
Room.    ! 


i...,., -J       r.:'..,,'.  i      L'-'zzq: 


~7 


Piajja.  Platform. 


Sketch  Showing  Ground  Plan  of  Milk  House  Owned  by  J.  D.  Farrell,  Esq., 
Renton,  Washington. 

eight  inches  deep  and  one  foot  wide.  The  gates  forming  the  front  of 
each  stall  are  forty-two  inches  in  their  perpendicular  measurement. 
They  are  adjustable  and  affixed  to  the  top  and  sides  of  the  stall  by 
small  chains  with  hooks  on  the  end. 

For  the  larger  cows,  the  upper  part  of  the  gate  may  be  tipped 
forward  and  fastened  to  an  extension  of  the  top  rod  forming  the  side 
of  the  stall  (see  Fig.  79).  In  the  case  of  the  smaller  cows,  the  top  of 
the  gate  is  tipped  backward  toward  the  manure  trench,  crowding  the 
cow  back  so  as  to  make  her  stand  on  the  edge  of  the  manure  trench 
(see  Fig.  79). 

The  milk  from  the  stable  is  brought  into  the  wash  room  and  is 
hoisted  onto  a  raised  platform  and  poured  into  a  strainer  marked  (i)t 


324  CLEAN  MILK 

from  which  elevation  it  flows  into  a  funnel  and  conducting  tube  through 
the  wall  into  the  collecting  tank  for  the  Star  cooler  (2)  and  cream 
cooler  (3).  From  this  collecting  tank  a  tube  also  supplies  the  separa- 
tor (4),  see  Fig.  83.  The  raised  platform  shown  in  Fig.  Si  was  a 
mistake,  as  it  should  have  been  lowered  so  far  as  would  permit  a  man 
standing  on  it  to  pour  the  milk  into  the  strainer  shown.  It  is  much 
too  high,  and  the  platform — instead  of  requiring  a  ladder — would  have 
only  required  a  few  steps  leading  up  to  it.  The  tank  under  the  plat- 
form was  intended  to  hold  cracked  ice,  on  which  water  was  to  be 
sprayed  for  supplying  the  ice  water  section  of  the  Star  cooler  in  sum- 
mer. But  this  was  found  unnecessary,  as  a  cask  could  be  placed  on 
the  floor  containing  a  coil  of  pipe  to  cool  the  water  as  described  on 
p.  116.  The  numbers  (5  and  6)  in  the  milk  room  are  supposed  to 
represent  the  bottle  filling  apparatus  for  milk  and  cream  shown  in 
plate.  The  bottles,  when  filled,  are  kept  over  night  in  a  series  of 
tanks,  one  over  the  other  (7),  as  water  is  had  from  a  neighboring 
spring  at  a  temperature  of  46  deg.  F.  to  fill  the  tanks.  The  bottles 
are  shipped  on  ice  in  galvanized  iron  cases.  The  empty  bottles 
are  delivered  on  the  elevated  piazza  platform,  in  front  of  the  wash 
room,  and  the  bottles  and  all  the  milk  utensils  are  washed,  put  in 
the  sterilizer  and  taken  out  through  the  other  door  in  the  milk  room 
when  it  is  desired  to  use  them.  The  milk  room  is  only  connected 
(with  one  door)  with  the  shipping  room  and  is  ventilated  by  a  system 
similar  to  that  recommended  for  barns.  The  floors  of  all  the  rooms  in 
the  milk  house  are  of  cement,  and  the  walls  of  cement-plaster,  covered 
with  many  coats  of  white  enamel  paint.  The  cement-plaster  is  laid  on 
wooden  laths  and  the  construction  of  the  building  is  of  wood.  It  is 
steam  heated  in  the  lavatory  and  wash  room.  The  climate  is  very 
mild  hereabouts  and  rarely  gets  much  below  freezing. 

Sketches  of  the  barn  and  milk  house  owned  by  IV.  H.  Paulhamus, 
Esq.,  are  reproduced  here  with  the  hope  that  they  may  prove  of  prac- 
tical value  to  those  intending  to  handle  clean  milk  on  a  considerable 
scale  for  profit. 

The  barn  (Fig.  84)  is  built  of  wood  and  eeiled  within  with 
smooth,  matched  boards  (shiplap)  painted  with  cold  water  white 
paint.  The  space  between  the  outer  and  inner  boarding  of  the  walls 
is  filled  in  with  sawdust.     The  inside  of  the  barn  is  eleven  feet  high,, 


Vi  a 

8.S- 


5^ 
a  % 


%¥ 


o  o 


PLANS   OF  BARNS  AND  MILK  ROOMS 


325 


^which  is  higher  than  is  generally  permissible  with  the  King  system  of 
ventilation  to  prevent  loss  of  animal  heat. 

The  climate  is,  however,  extremely  mild,  the  temperature  seldom  ' 
dropping  much  below  freezing  in  winter  hereabouts.  The  King  system, 
is  nevertheless  followed  ;    there  being  ten  inlets,  between  ten  windows, 

Fig.  85. 


8-.. 


JO 


L7, 

\ 
.••■2 

s 

- 

i 

°\ 

J 

6 

' 

8' 

--7 

\  ® 


)-^% 


5/1 


l.^NSY'^NV'TiP. 


to 


35' 

Kough  Sketch  of  Ground  Plan  of  Barn  for  Forty  Cows,  W.  H.  Paulhamus,  Esq. 
Sumner,  Washington. 


(10)  on  each  side  of  the  barn,  near  the  ceiling.  These  openings  are 
six  by  six  inches,  and  bring  the  air  in  shafts  between  the  layers  of  the 
walls  of  the  building  from  a  point  outside  near  the  ground.  The 
windows  in  the  sides  of  the  barn  are  three  and  one-half  feet  square, 
and  between  them  in  the  sketch  may  be  seen  lines  (No.  8)  showing 
the  point  of  entrance  of  the  inlets  for  fresh  air. 

The  shafts  for  outlet  of  air  are  in  the  opposite  corners  of  the 


326         '    '  '  CLEAN  MILK 

building  (7)  and  are  two  feet  square  with  openings  at  the  floor  of 
the  same  dimensions. 

One  special  feature  is  the  arrangement  of  the  cement  which  covers 
the  whole  floor,  except  as  noted.  The  entire  floor  slopes  about  one 
foot  from  one  end  of  the  building,  so,  while  the  gutters  are  the  same 
depth,  this  permits  of  a  flow  for  drainage.  The  cows  face  the  outside 
of  the  building  and  the  floor  of  their  stalls  is  of  two  inch  matched, 
planed  Oregon  pine,  except  for  a  strip  of  cement  eight  inches  wide  on 
the  side  of  the  gutter  (6)  on  which  the  hind  feet  of  the  animal  rest. 
All  the  rest  of  the  floor  back  of  the  cows  is  of  concrete  with  cement 
finish,  while  the  side  aisles  in  front  of  the  cattle  are  of  wood,  like  the 
floor  of  the  stalls.  The  cows  do  not  have  the  slippery,  cold,  cement 
floor  to  lie  (or  fall)  upon,  which  Mr.  Paulhamus  believes  an  improve- 
ment over  an  entire  cement  floor.  The  stalls  are  shown  in  Plate  IX. 
There  are  so  many  kinds  of  stalls  that  it  is  impossible  to  say  which  is 
the  best,  but  these  are  simple,  inexpensive  and  satisfactory,  as  soon  as 
the  cows  get  used  to  them. 

At  one  end  of  the  barn  are  several  rooms.  One  (1)  is  intended 
for  keeping  supplies,  as  baled  hay,  roots  and  grain  in  sacks,  etc.  One 
on  the  opposite  side  is  a  wash  room  with  sink  and  hot  and  cold  water 
(B),  and  a  sheet  iron  stove  (A)  for  wood  with  a  coil  of  pipe  inside  to 
heat  water  (see  p.  120).  There  is  also  a  closet  id)  for  keeping  the 
milking  clothes.  The  next  room  (3)  is  a  rather  novel  arrangement  of 
the  owner  and  assuredly  deserves  attention. 

This  room  has  no  connection  with  the  inside  of  the  barn,  except 
by  a  tube  for  conveying  milk  at  C.  Here  may  be  found  a  pair  of 
steps  which  each  milker  ascends  the  moment  he  fills  the  pail.  The 
milk  is  poured  into  a  sterile  tin  funnel  which  carries  it  onto  a  Star 
cooler*,  from  which  it  falls,  immediately  cooled,  into  a  can.  The 
can,  when  full,  is  taken  to  the  milk  house  (Fig.  S7),  some  200  feet 
away. 

The  room  (3)  is  reached  from  outside  the  barn  and — with  screened 
door  and  window,  and  smooth,  clean,  painted  walls  and  ceiling,  and 


*The  milk  flows  from  the  funnel  (which  is  in  the  open  central  aisle  of 
bar«)  through  the  wall,  which  separates  it  from  room  3,  and  in  that  room  falls 
the  cooler. 


the 

Oil 


gs 


52   m 

0  a 
o  <u 


PLANS   OF  BARNS  AND  MILK  ROOMS 


327 


cement  floor — makes  a  good  place  for  immediate  cooling  of  the  milk. 
The  horizontal  ceiling  of  the  barn  leaves  much  space  in  the  roof,  in 
which  grain  is  stored.  The  grain  is  brought  down  in  spouts  to  the 
bins  at  (2)  and  hay  could  be  delivered  from  the  loft  above  in  the 
room(i)  without  causing  any  dust  in  the  barn.  The  ceiling  of  the 
tarn  is  absolutely  dust  tight  with  double  floor  and  paper  between. 

The  barn  is  one  hundred  by  thirty-five  feet   inside  ;  the  centre 

Fig.  87. 


^ 


Rough  Sketch  of  Ground  Plan  of  Milk  House.    W.  H.  Paulhamus,  Esq., 
Sumner,  Washington. 

aisle  eight  feet,  and  gutters  eighteen  inches  wide.  The  side  aisles  are 
five  and  one-half  feet  wide. 

Box  stalls  for  sick  cows,  or  cows  about  to  calve,  are  in  another 
building. 

The  buildings  used  for  the  milk  rooms  (Fig.  87)  proper  were 
altered  for  their  present  purpose  and  were  situated  farther  from  the 
barn  than  is  necessary  or  desirable. 

A   sketch   of    the    ground    plan    of    the   milk  house   is   shown 


The  floors  of  the  milk  room  and  wash  room  are  of  concrete  with 


328  CLEAN  MILK 

cement  finish,  boarded  inside  with  planed,  matched  boards  (walls  and 
ceiling),  painted  white  and  ventilated  after  the  King  system.  The 
space  between  the  inner  and  outer  layer  of  the  walls  is  stuffed  with 
sawdust  and  the  rooms  are  very  high-studded  (fourteen  feet).  The 
sterilizer  (S)  is  wholly  of  concrete,  which  is  described  on  p.  127,  and, 
if  the  buildings  had  not  been  already  built  before  they  were  put  to 
their  present  use,  it  is  probable  that  the  most  convenient  place  for  the 
sterilizer  would  have  been  in  the  wall  between  the  wash  and  milk 
rooms,  as  in  Mr.  Farrell's  (Figs.  82  and  83).  The  sterilizer  is  supplied 
with  steam  from  the  20- horse  power  boiler  (6)  in  the  wash  room. 

This  sterilizer  is  an  original  feature  introduced  by  Mr.  Paulhamus 
and  works  beautifully.  It  is  of  enormous  size  (see  p.  127  and  Fig.  88) 
and  very  inexpensive,  costing  some  $So.  In  cold  climates  it  would  have 
to  be  inside  the  building  as  suggested  above.  Another  novel  feature  is 
the  washing  machine  shown  as  (No.  12)  in  the  sketch  in  the  wash  room. 
This  was  patented  after  its  introduction  at  Mr.  Paulhamus's  farm  and 
now  sold  by  The  Chas.  H.  Lilly  Co.,  of  Seattle.  The  machine  con- 
sists of  four  tanks,  a,  b,  and  c,  dfand  e.  In  a,  is  held  warm  water,  in 
b  and  c,  is  contained  alkali  and  warm  water,  and  in  d,  is  plain  warm 
water.  The  three  lines  {g)  running  lengthwise  in  the  sketch,  through 
the  middle  of  the  machine,  represent  three  pipes  running  over  the  top 
of  the  tanks.  These  pipes  are  perforated  with  holes  which  are  placed 
so  as  to  correspond  with  the  opening  in  each  milk  bottle  when  the 
bottles  are  inverted  on  wooden  trays.  Each  wooden  tray  is  made  of 
slats  which,  in  crossing,  leave  holes  fitting  the  neck  of  an  inverted  milk 
bottle.  The  trays  holds  twenty-four  bottles  in  three  rows,  so  that 
when  the  tray  is  slid  in  place  on  top  of  the  machine,  each  row  of  bot- 
tles is  over  one  of  the.  three  pipes  in  the  centre  of  the  machine,  and 
each  bottle  is  inverted  over  one  of  the  perforations  in  the  pipes.  On 
one  side  of  the  machine  are  three  rotary  pumps  {/)  worked  by  the 
engine  at  (7).  These  continually  pump  water  from  the  tanks  into  the 
the  pipes,  from  which  it  is  forced  out  in  jets  into  the  interior  of  each 
inverted  milk  bottle.  The  water  then  runs  out  of  the  bottles  back 
into  the  tank  over  which  the  bottles  are  resting.  The  pipe  shown  on 
either  side  of  the  top  of  the  machine  at  (//)  is  perforated  with  holes 
from  which  water  is  thrown  over  and  cleans  the  outside  of  the  bottles 
as  they  are  pushed  through  the  machine. 


Fig.  88. 


This  photograph  shows  the  interior  of  the  large  all-concrete  and  cement 
sterilizer  at  the  Paulhamus  farm.  The  door  is  of  iron.  All  the  dairy  utensils 
■which  come  in  contact  with  milk  in  any  way  are  put  in  this  chamber  and  kept 
at  2X2°  F  for  one  hour  daily.    For  description,  see  p.  127, 


PLANS   OF  BARNS  AND  MILK  ROOMS  329 

The  method  of  working-  is  as  follows  :  A  tray  holding  twenty- 
four  inverted  bottles  is  placed  on  the  top  of  the  machine  over  the  tank 
(a).  The  warm  water  in  the  central  pipes  is  pumped  up  through  the 
holes  in  the  pipes  into  each  bottle,  thus  rinsing  it  out.  Another  tray 
being  pushed  into  the  machine  shoves  the  first  tray  over  tank  (£). 
Here  the  interior  of  the  bottles  is  sprayed  with  lye  and  water.  The 
introduction  of  another  tray  moves  the  first  tray  over  the  tank  (c). 
The  tank  (c)  is  really  one  with  (£),  the  bottles  here  merely  draining 
back  into  the  tank  again,  no  water  being  pumped  into  them.  Another 
tray  being  placed  in  the  machine  pushes  the  first  tray  to  (d).  Here 
the  bottles  are  rinsed  with  plain  warm  water  to  remove  the  lye,  and, 
at  (e),  boiling  water  is  injected  instead  of  water  to  sterilize  (for  one 
minute)  the  bottles.  About  1 ,  500  bottles  may  be  washed  in  one  hour  by 
this  labor-saving  device.  The  bottles  must,  however,  be  washed  by  hand 
if  they  contain  old  milk  and  have  not  been  previously  rinsed  by  the 
milk  consumer.  Also,  one  minute  sterilization*  is  not  sufficient  and 
they  must  go  for  one  hour's  sterilization  in  the  large  sterilizer,  when 
certified  milk  is  desired.  The  water  is  heated  by  steam  from  the 
boiler  (6)  which  runs  the  engine.  A  metal  hood  covers  the  whole  top 
of  the  washing  machine  to  prevent  the  escape  of  the  water  which  is 
thrown  from  the  pipes  on  each  side  over  the  exterior  of  the  bottles. 
The  machine  with  pumps  costs  about  $ 200,  and  is  sixteen  feet  long 
and  twenty-six  inches  wide  (see  Fig.  86). 

The  platform  (13)  and  floor  of  the  milk-receiving  room  are  some 
fifty  inches  from  the  ground.  In  the  milk-receiving  room  at  (9)  is  a 
raised  platform  three  feet  from  the  floor  on  which  are  scales  holding  a 
large  milk-receiving  tank  in  which  is  a  Star  trap  strainer.  After  the 
milk  is  weighed  it  is  run  from  a  faucet  into  a  funnel,  conducting  the 
milk  through  the  wall,  into  a  tank  (10)  holding  some  one  hundred 
gallons,  and  from  thence  is  drawn  off  into  the  Star  bottle  filling  tank 
(11).  The  milk  is  cooled,  as  described,  at  the  barn  (p.  328),  and  the 
water  supplying  the  Star  cooler  is  cooled  in  summer  by  running  it 
through  a  coil  of  pipe  in  a  cask  of  ice  water  (see  p.  116). 


*  It  is  perfectly  possible  to  sterilize  milk  bottles  absolutely,  if  boiling  water  is 
pumped  into  the  bottles  for  a  longer  time,  as  shown  Dy  bacteriological  examina- 
tions of  bottles  washed  by  similar  machines.  The  exhaust  steam  from  the  engine 
may  be  used  to  heat  water  to  boiling  point. 


33° 


CLEAN  MILK 


A. sketch  of  the  cow  stall  used  by  Mr.  Paulhamus  is  shown  in 
Fig.  89. 

The  floor  has  been  described  (p.  32S)  as  consisting  of  cement  for 
eight  inches  in  front  of  the  gutter  and  (forward  of  this  point)  of  two 
inches  kiln-dried,  planed,  tongued  and  grooved  Oregon  pine.  The 
dimensions  are  marked  in  the  sketch,  but  the  length  of  the  stalls  vary 

Fig-  39. 


Side  and  Rear  View  of  Stall  in  Cow  Stable  of  W.  H.  Paulhamus,  Esq., 
Sumner,  Washington. 


from  four  and  one-half  feet  to  five  feet  long,  from  the  gutter  to  the 
manger,  to  accommodate  cows  (Jerseys)  of  different  sizes.  The  floor  of 
the  stall  slopes  some  three  inches  from  front  to  rear.  The  stalls  begin 
four  and  one-half  feet  long  at  one  end  of  the  stable  and  gradually 
lengthen  till  they  are  five  feet  long  at  the  other  end.  Each  side  of 
stall  is  really  a  gate  opening  toward  the  right,  to  give  more  room  to 
the  milker  and  groomer,  when  open.  They  could  of  course  be  hung 
on  hinges  so  as  to  swing  in  cither  directi  ,... 


Fig.  90.— The  improved  "  Drown"  Stall. 


View  shows  cement  mangers  and  floors  fitted  -with  iron  stalls  having  two-way 
movable  partitions. 


The  Drown  Stall  is  one  of  the  best  made  and  is  an  improvement  over  either 
stall  shown  in  that  the  side  gates  give  more  room  to  the  attendant  and  open  in 
either  direction  sideways  and  also  upward.  The  raised  feeding  trench  and  hay 
rack  are  good  features. 

The  stall  is  patented  and  sold  by  M.  L.  Drown,  of  Madison,  Wis.  It  is  in 
use  by  some  of  the  agricultural  experiment  stations  and  leading  dairy  farmers 
of  this  country. 


PLANS  OF  BARNS  AND  MILK  ROOMS  33 1 

The  gates  are  fastened  with  a  wooden  sliding  bolt  (not  shown). 
The  bottom  of  the  rear  posts  may  (for  the  lower  eighteen  inches) 
consist  of  galvanized  iron  pipe  set  below  in  the  cement  and  above  in 
the  wooden  scantling,  for  the  sake  of  cleanliness.  At  the  rear  of  the 
stall  is  seen  a  chain  which  is  attached  to  rings  in  the  post,  on  either 
side  of  the  stall,  by  means  of  snap  hooks.  The  manger  has  two  com- 
partments, the  lower  for  grain,  and  the  upper  or  forward  being  for 
hay — with  a  sliding  rack  between  the  two  which  may  be  removed  or 
lifted  a  little  to  clean  out  the  floor  of  the  manger.  (Sometimes  the 
whole  manger,  arranged  with  sides  reaching  to  the  floor  of  the  stable, 
is  made  movable  so  that  it  may  be  adjusted  to  the  length  of  the  cow 
and  locked  by  pegs  fitting  in  the  side  posts.)  The  cross-piece  at  (C)  is 
necessary  to  keep  the  cows  from  pressing  forward  and  climbing  over 
the  manger.  It  must  be  adjusted  somewhat  to  the  height  of  the  cow. 
This  stall  is  convenient  and  inexpensive  as  compared  to  the  iron  stalls 
(Figs.  79,  81).  There  is  nothing  on  the  floor  of  the  stable  to  col- 
lect dirt,  as  the  manger  does  not  touch  the  floor,  but  is  eight  inches 
above  it. 

We  present  a  method  of  fastening  cows  (Fig.  91)  without  the  use 
of  stalls.  In  this  the  animals  are  tied  by  swing  stanchions.  These  are 
greatly  superior  to  the  old  style  of  fixed  wooden  stanchions  in  allowing 
free  movement  of  the  cows.  No  partition  is  used  between  the  cows' 
bodies,  but  one,  as  seen  in  the  cut,  is  placed  in  the  feed  trough 
separating  the  cows'  heads.  It  has  the  advantage  of  being  a  simple, 
cleanly,  compact  and  cheap  method  of  housing  cows.  Compact  and 
cleanly  in  avoiding  gates  between  cows,  which  collect  dirt,  it  has  the 
disadvantage  of  not  keeping  the  cows  so  well  separated  as  when  there 
Is  a  partition  between  each  animal,  and  it  can  not  be  arranged  to 
conform  to  the  length  of  each  animal  as  can  stalls  with  a  movable 
gate  in  front  of  each  cow.  It  is  widely  used  and  by  many  good 
authorities  is  regarded  as  the  best  method  of  fastening  animals  in 
the  barn. 

The  feed  trough  or  manger  is  seen  to  be  hollowed  out  of  cement, 
with  cement  partitions  in  it  between  each  cow.  On  top  of  each 
cement  partition  is  one  of  wood,  to  which  water  buckets  may  be 
attached.  The  wood  base  of  the  stanchions  should  not  rise  above  the 
level  of  the  cement  floor  in  order  that  sweeping  and  cleaning  can  be 


CLEAN  MILK 

more  readily  done.  In  the  upper  part  of  the  cut  is  seen  a  cross 
section  of  a  barn  floor  arranged  for  two  rows  of  cows  facing  one 
another.  The  feeding  alley  between  the  two  rows  of  cows  is  nine  feet 
wide  ;  the  feeding  trough  is  two  feet  wide  ;  the  length  of  the  standing 
space  for  the  cows  is  five  feet  six  inches  (varying  with  the  size  of  the: 


Sft.    6in-rV?!fe> 


Fig.  91. 


Swing  Stanchion  and  Cross  Section  of  Feed  Trough. 
(From  Bull.  No,  53,  Storrs  Agricultural  Experiment  Station.) 


cows)  ;  the  manure  trench  is  sixteen  inches  wide  ;  the  alley  behind 
the  cows  is  five  feet  wide. 

Another  arrangement  for  swing  stanchion  ;  fixed,  iron  partition  ; 
and  removable,  wood,  paneled  floor  over  concrete  is  shown  in  the 
accompanying  cuts  (Fig.  92). 

These  and  the  following  plans  for  milk  rooms,  a  creamery  and 


PLANS  OF  BARNS  AND  MILK  ROOMS  333 

city  milk  plant,  and  a  creamery  for  whole  milk,  are  taken  from  Bull. 
104,  U.  S.  Bureau  of  Animal  Industry. 

Fig.  92. 


Stall  with  panel  wooden  floor. 

3.  Swing  stanchion.     2.  Showing  wooden   floor,  viewed   from   above.     3.   Stall 

from  the  front.     4.  Side  view  of  stall  and  cross  section  of  floor. 


Fig-  93- 


DIMENSION'S 


Shows  a  small  dairy  house  suitable  for  the  general  needs  of  a  herd  of  25  to  30 
cows.  A  is  the  ice  box  ;  B,  butter  worker  ;  C,  heater  ;  £>,  churn  ;  E, 
cream  vat ;  E,  trap  to  sewer  ;  G,  cooler  ;  H,  separator  ;  /,  can  and  pail 
rack.  If  this  house  is  built  of  wood,  the  brick  chimney  should  be  built 
outside  the  frame. 


334 


CLEAN  MILK' 


Fig.  94- 


Floor  plan  of  small  plant  for  certified  milk  connected  with  barn.  A  A  are  coal 
bunkers  ;  B,  boiler  ;  C,  sterilizer ;  D,  shower  bath  ;  E,  bottling  table  ; 
F,  cooler  ;   C,  receiving  can. 


Fig-  95- 


o/r?£A/s/oMS  7s-  av  a  w.a: 

Floor  plan  of  creamery  and  city  milk  plant. 


CONCENTRATED  MILK 

Fig.  96. 


335 


Front  elevation  of  creamery  and  city  milk  plant  shown  in  Fig.  95. 
Fig.  97. 


Floor  plan  of  creamery  for  whole  milk. 

In  the  plan  as  shown  A  is  the  pump ;  B,  boiler;  C,  ice  machine  ;  D,  engine  ; 
E,  skim  milk  weigher  ;  F,  churn  ;  G,  sink  ;  H,  milk  vat ;  /,  weighing 
,Jank ;  K,  separator  ;  L,  cream  vat ;  M,  table. 

Concentrated  Milk 

^This  is'a  new  product,  made  by  a  patented  process,  whereby  the 
cream  is  separated  from  the  milk  and  pasteurized,  while  the  skim 
milk  is  heated  for  two  hours  at  1400  F.  and  reunited  with  the 
pasteurized  cream.  The  resulting  concentrated  milk  is  used  by 
diluting  it  with  three  parts  of  water. 

When  thus  diluted  it  appears  to  have  the  taste,  appearance  and 
all  the  properties  of  ordinary  fresh  milk.  It  is,  however,  free  from 
all  disease-producing  germs,  including  those  causing  the  infectious 
and  diarrheal  disorders  and  tuberculosis. 

The  reason  of  its  unaltered  taste  and  pltysical  properties  lies  in 
the  low  temperature  (1400   F.)   at  which  it  is  pasteurized,  and  the 


336 


CLEAN  MILK 


reason  for  the  effective  destruction  of  disease  germs  is  due  to  the  long 
period  of  heating  (two  hours). 

Concentrated  milk  is  of  small  bulk  and  may  therefore  be  trans- 
ported cheaply.  It  must,  however,  be  kept  at  500  F.,  and  even  at 
this  point  germs  may  become  abundant  after  a  few  days.  Thus, 
Conn  states,  after  six  days  concentrated  milk  may  contain  a  number 
approaching  500,000  bacteria  to  the  cubic  centimeter — even  though  it 
be  kept  cool.    These  bacteria  are  harmless  and  the  milk  is  not  soured. 

Concentrated  milk,  when  properly  diluted  (1  to  3),  will  cost  the 
consumer  just  about  what  ordinary  fresh  milk  does. 

It  is,  nevertheless,  extremely  doubtful  whether  concentrated  milk 
will  supersede  fresh,  clean  milk,  although  it  is  a  great  improvement 
over  dirty  milk.  My  reason  for  this  assumption  is  that  milk  is  taken 
largely  in  the  household  for  its  cream,  for  use  on  the  table  and 
for  infant  feeding. 

All  handling  of  milk  disturbs  and  lessens  to  some  extent  the 
complete  rising  of  cream.  When  milk  is  simply  cooled  and  bottled  at 
the  farm,  the  cream  has  already  completely  separated  when  it  reaches 
the  consumer's  house  (in  most  cases),  and  may  be  immediately  re- 
moved for  use.  This  statement  cannot  be  applied  to  concentrated 
milk. 

Milking  Machines. 

The  milking  machine,  together  with  the  single  service  paper  milk 
bottle,  bid  fair  to  practically  revolutionize  the  methods  of  producing 
clean  milk. 

If  these  two  inventions  prove  as  valuable  as  they  promise,  the 
whole  question  of  clean  milk  production  will  be  solved.  The  milk 
will  be  obtained  nearly  sterile  and  be  immediately  cooled  and  run  into 
sterile  bottles.  The  status  of  the  milking  machine  seems  still  a  matter 
of  some  uncertainty  with  every  indication  of  a  successful  future.  The 
machine  we  will  describe  appears  to  be  one  of  the  most  efficient 
and  has  been  in  operation  for  some  years.  At  present  it  is  being  used 
by  the  leaders  in  the  dairy  industry,  as  by  the  Walker-Gordon  people. 

The  Burrell-Lawrence-Kennedy  Cow  Milker  comprises  the 
following  : 


MILKING  MACHINES  .  337 

1.  A  vacuum  pump  operated  by  power,  steam,  electric  motor, 
gas  engine,  tread  mill  (bull),  a  head  of  water  over  thirty  feet,  etc. 

2.  One  inch  iron  piping  connecting  the  vacuum  pump  with  a 
vacuum  tank,  supplied  with  gauge  and  safety  valve,  and  thence 
about  the  barn  for  attachment  to  the  milkers. 

3.  The  Milkers. — A  milker  consists  of  a  milk  pail  (heavy  enough 
to  withstand  a  vacuum),  on  which  is  placed  a  pulsator,  which  in  its 
turn  is  connected  with  one-half  inch  rubber  tubing  to  four  teat  cups 
fitted  on  the  teats  of  the  cow. 

The  vacuum  is  about  equal  to  one-half  an  atmosphere,  fifteen 
to  seventeen  inches,  and  the  vacuum  tank  is  connected  with  the 
system  to  insure  a  uniform,  safe  and  known  suction.  The  pulsator 
(Fig.  99)  is  the  salient  feature  of  this  .machine.  It  rests  on  top 
of  the  milk  pail,  to  which  it  fits  tightly  as  soon  as  the  exhaust  is  turned 
on,  because  of  atmospheric  pressure  and  because  it  rests  on  a  rubber 
gasket.  The  pulsator  is  connected  with  the  iron  pipes  wdiich  run 
along  over  the  stanchions  (Fig.  98)  by  one-half  inch  rubber  tubing 
fitted  to  the  nipple  at  its  base.  The  two  stop-cocks,  seen  in  the  plate 
of  the  pulsator,  are  each  connected  with  rubber  tubes,  one  taking  the 
milk  from  the  four  teats  of  a  cow  on  one  side,  and  the  other  from  the 
cow  to  the  other  side  of  the  pulsator. 

When  the  machine  is  in  operation  the  cow's  udder  is  cleaned,  the' 
teat  cups  (of  five  sizes)  are  adjusted,  and  a  milk  pail — placed  between 
each  two  cows — is  surmounted  by  a  pulsator  attached  by  rubber  tub- 
ing, both  to  the  iron  piping  above,  and  to  the  teats  of  the  cows  on 
each  side  (Fig.  9S).  That  is,  each  milker  (milk  pail,  pulsator,  rubber 
connections  and  teat  cups)  is  capable  of  milking  two  cows  at  the  same 
time.  A  stop-cock  is  turned  and  the  suction  applied  by  the  pulsator  to 
the  cow's  teats.  By  this  mechanism  there  is  exerted  intermittently 
not  only  suction  but  also  compression  on  the  outside  of  the  teat,  simu- 
lating the  action  produced  in  hand  milking.  Glass  windows  in  the 
tubing  leading  from  the  teats  inform  the  operator  as  to  the  flow  of 
milk.     Most  cows  do  not  object  to  the  use  of  the  machine. 

This  machine  will  practically  prevent  the  initial  contamination  of 
milk,  and  will  render  the  production  of  clean  milk  more  simple  and 
easy  than  by  any  method  heretofore  known.  But  the  greatest  care 
is  necessary  to  achieve  this  result. 


33S  CLEAN  MILK 

Stocking  and  Mason*  have  made  elaborate  experiments  to  deter- 
mine the  best  way  to  cleanse  and  sterilize  the  rubber  tubing  and  teat 
cupsof  milking  machines.  They  found  that  bacteria  multiply  rapidly 
in  ten  per  cent,  brine  solution,  which,  has  been  commonly  used. 
Continuous  sterilization  of  rubber  by  boiling  water  or  steam  for  a 
proper  period  to  sterilize  is  destructive  to  the  rubber  parts.  The 
method  finally  adopted. was  to.  first  rinse  the  tubing  and  teat  cups 
withclean  water  after  each  milking.  This  is  done  by  connecting  the 
machine  to  the  vacuum  system  near  a  sink,  and,  by  plunging  the  teat 
clips  in  the  sink,  clean  water  is  drawn  through  the  teat  cups  and 
tubing  into  the  milk  pails.  The  next  step  consists  in  soaking  the 
teat. clips. and  rubber  tubing,  in  a  3jj.per  cent,  solution  of  formalin  in 
water  between  milkings.  Just  before  milking  the  rubber  tubing  and 
teat  cups  are  again  thoroughly  rinsed  in  clean,  boiled  water.  The 
milk  pail  and  pulsator  are  sterilized  by  steam  in  a  sterilizer  or  by 
boiling. in  water. 

By  the  above  method  the  bacterial  content  of  milk  withdrawn 
by  machine  was  about  the  same  as  that  obtained  by  hand  under 
cleanly  conditions  iu  the  same  stable.  In  order  to  secure  the  best 
results  a  thin  layer  of  absorbent  cotton  is  placed  in  the  air-relief  of  the 
teat  cup  connector  and  of  the  head  of  the  machine  to  filter  the 
bacteria  from  the  stable  air.  At  these  two  points  the  air  rushes  in  at 
each  pulsation  of  the  machine  to  relieve  the  vacuum.  After  doing 
this  the  bacteria  in  the  machine-drawn  milk  (averaging  1,578  bacteria 
per  c.  c.)  were  reduced  to  about  one-third  of  those  in  the  milk  drawn 
by  hand  (averaging  4,560  bacteria  per  c.  c.)  under  like  conditions. 
The  milk  from  the  milking"- machine  kept  twice  as  long  as  the  milk 
withdrawn  by  hand,  i.  c,  milk  at  72  degrees  soured  after  38  hours 
when  withdrawn  by  hand  ;  machine-drawn  milk  kept  sweet  for 
72  hours. 

The  only  objection  to  the  use  of  formalin  in  keeping  the  parts  of 
the  milking  machine  clean  1  is  the  possibility  of  milk  being  con-' 
taminated  by  a  trace. of  it.  The  presence  of  formalin  in  milk  is 
illegal  and  would  prove  to  be  the  greatest  misfortune  to  one  supplying 
a  high   grade  of  milk,   as   suggesting  the  possibility   of   intentional 


Storrs  Agricul.  Exper.  Sta.  Bull.  47,  May,  1907. 


Fig.  9S. — The  Burrell-Lawrence-Kennedy  Cow  Milker. 


The  plate  shows  the  main  iron  piping  above  the  stanchions  connected  by 
rubber  tubing  with  the  pulsators  placed  on  top  of  each  milk  pail  between  each 
two  cows. 


Fig.  99. — The  Pulsator. 


Pig.  too.— Illustiatiug  the  Hegelund  method  of  milking. 


Fig,  i. — First  manipulation  of  udder, 
right  quarters. 


Fig.  2.— First  manipulation,  left  quarters. 


Fig.  3.— Second  manipulation,  right  fore  quarter. 


FlG  4. — Second  manipulation, 
right  hind  quarter. 


. 

u 

1.  - 

w* 

Mm 

FlG.  5. — Second  manipulation, 
right   hind   quarter,    rear   view. 


Fig.  6.— Third  manipulation. 


MILKING  MACHINES  339 

adulteration  with  this  preservative.  Stocking  found  no  trace  of 
formalin,  however,  in  milk  obtained  from  milking  machines  thus 
treated.  From  the  viewpoint  of  this  book  the  chief  benefit  of  milking 
machines  is  the  lowering  of  the  germ-content  of  milk  made  possible 
by  them.  But  this  result  has  been  by  no  means  always  secured  and 
can  not  be  unless  the  greatest  care  is  given  to  the  cleansing  of  all  the 
parts. 

As  a  labor-saver  the  device  enables  one  man  to  do  four  men's 
work.  One  man  can  operate  three  or  four  milkers  at  once,  each  milk- 
ing two  cows  at  the  same  time,  which  means  that  he  can  milk  thirty 
to  forty  cows  an  hour.  With  hand-milking  this  number  of  cows 
would  require  the  work  of  four  men  for  one  hour. 

Moreover,  the  results  are  much  more  uniform,  and  daily  variations 
in  milk-yield,  depending  on  the  personality  of  the  milker,  are 
eliminated. 

The  difficulties  in  keeping  milkers  and  the  disastrous  results  from 
frequent  change  of  milkers  are  also  removed  by  the  machine. 

Cost. — The  expensive  parts  of  the  milking  machine  are  the 
milkers  and  the  vacuum  pump,  each  of  these  costing  $75  apiece.  This 
pump  is  capable  of  operating  five  milkers.  The  entire  cost  of  the 
installation,  power  -and  milking  machines  is  estimated  by  the  sellers 
to  amount  to  about  $12.00  per  cow  for  a  herd  of  forty  cows,  and  $8.50 
per  cow  for  a  herd  of  seventy-five.* 

With  accumulating  experience,  the  results  obtained  by  the  use  of 
the  Burrell-L,awrence-Kennedy  milking  machine  appear  to  be  gener- 
ally favorable. 

The  more  common  doubts  as  to  the  amenability  of  cows  to  the 
milking  machine,  and  the  danger  of  drying  up  cows  from  incomplete 
emptying  of  the  udder,  have  been  dispelled.  Cows  hitherto  unruly  to 
hand  milking,  and  heifers  never  milked  before,  have  taken  most 
kindly  to  the  machine,  and,  on  the  whole,  cows  like  machine  milking 
better  than  hand  milking. 

Experiments  appear  to  show  that  the  milk  yield  is  about  the  same 
in  hand  milking  and  machine  milking,  providing  that  the  teat  cups 

*  For  details  consult  D.  H.  Burrell  &  Co,,  Little  Falls,  N.  Y.,  and  Brock- 
ville,  Ont. 


340  CLEAN  MILK 

are  carefully  fitted.  Also  the  udder  appears  to  be  emptied  even  more' 
thoroughly  by  the  machine  than  by  hand — exclusive  of  stripping. 
The  chief  objection  to  the  machine  is  its  initial  expense,  while,  on  the 
other  hand,  its  chief  value  lies  in  its  saving  of  money  and  labor  in  its 
operation. 

Hand  stripping — after  the  removal  of  the  teat  cups — is  done, 
generally,  into  the  teat  cups  themselves.  Cows  which  are  milked  by 
the  machine  have  a  longer  period  of  lactation  than  when  milked  by 
hand. 

What  appeared  a  serious  objection  to  the  milking  machine  was 
the  complaint  that  the  milk  of  single  cows  could  not  be  separated  from 
that  of  the  herd — in  case  it  was  contaminated  with  blood  or  pus  and 
germs  from  an  inflamed  udder  ;  or  the  milk  was  needed  for  feeding  a 
calf  ;  or  for  making  a  periodical  test  for  quantity  and  fat.  Gurler 
has  obviated  this  defect  by  having  the  pail  of  one  machine  divided 
into  two  compartments,  one  for  each  cow,  and  provided  with  corres- 
ponding outlets  from  which  the  milk  from  each  cow  can  be  drawn. 
Garget,  and  all  troubles  with  the  udder,  are  less  frequent  with  the 
milking  machine — probably  because  the  teats  are  not  so  subject 
to  abrasions  and  infection  from  other  cows  by  the  hands  of  the 
milker. 

Mr.  H.  B.  Gurler,  of  Illinois,  one  of  the  most  noted  dairymen  of 
this  country — writing  in  Hoard's  Dairyman — says  that  in  thirty  com- 
parative tests  between  hand  and  machine  milking,  the  number  of 
bacteria  was  reduced  one-half  by  the  machine — from  5,000  to  2,500 
per  c.c.  After  fourteen  months'  use  of  the  Burrell-L,awrence-Kennedy 
machine  with  two  hundred  cows  he  found  but  two  or  three  cows 
which  could  not  be  milked  by  it ;  he  gives  it  his  unqualified  approba- 
tion and  affirms  that  it  has  come  to  stay. 

Gurler  states  that  one  man  with  the  machine  is  equal  to  three 
hand  milkers  ;  that  no  difficulty  was  experienced  in  keeping  the  appara- 
tus clean  by  the  use  of  rinsing  in  cold  water,  a  solution  of  lye,  and 
boiling  water  ;  and  that  great  care  should  be  taken  in  accurately 
fitting  each  teat  cup  to  each  individual  teat.  He  warns  against  com- 
pletely filling  the  milk  pails,  lest  milk  be  drawn  into  the  vacuum 
pipes,  and  emphasizes  the  necessity  of  a  uniform  vacuum.  If  a  teat 
cup  pulls  off  or  any  accident  occurs  which  reduces  the  vacuum,  the 


MILKING  MACHINES 


341 


machines  should  be  shut  off  till  the  proper  vacuum  is  secured. 
And  when  one  of  a  pair  of  cows  attached  to  a  machine  is  milked 
before  the  other,  the  vacuum  should  be  shut  off  from  that  cow,  at 
the  machine,  and  the  machine  kept  running  until  the  other  cow  is 
milked. 

Smaller  teat  cups  must  be  fitted  on  the  cows  after  they  have  been 
in  use  for  some  time,  as  the  rubber  mouthpieces  expand  and  teats 
grow  smaller  after  freshening  of  cows. 

Separate  stalls  for  milking  by  the  machine  may  be  placed  in  the 
basement  of  a  stable.  The  cows  run  loose  and  are  turned  into  the 
stalls  and  are  fed  grain  there  as  they  are  milked.  When  the  milking 
is  over  the  cow  passes  out  of  a  gate  in  front  of  the  stall.  So  no  time 
is  lost  if  one  of  a  pair  of  cows  is  milked  before  the  other.  A  small 
platform  set  between  each  pair  of  cows  affords  a  base  for  the  milking 
machine  and  a  seat  for  the  operator  in  adjusting  the  teat  cups. 

The  machine  is  indicated  for  farms  with  a  large  number  of  cows 
(fifty  or  over)  and  where  labor  is  expensive  and  difficult  to  obtain. 

The  Hegelund  Method.  — Extensive  experiments  with  this  method 
of  manipulating  the  udder  at  the  close  of  milking  have  been  conducted 
by  Woll  at  the  University  of  Wisconsin  Agricultural  Station,*  on  one 
hundred  and  fifty  cows  during  a  summer  and  fall,  and  have  proved  its 
advantages  to  be  as  follows  : 

A  daily  gain  of  one  pound  of  milk,  and  one-tenth  pound  of  fat 
per  cow  was  obtained.  This  is  equivalent  to  a  gain  of  about  thirty- 
five  pounds  of  butter  per  cow  per  annum. 

Most  cows  do  not  object  to  the  manipulation  ;  less  than  a  dozen 
out  of  the  number  tested  did  so. 

The  gain  in  quantity  of  milk  and  fat  is  not  a  temporary  increase  ; 
not  only  is  the  gain  persistent,  but  the  method  tends  to  maintain  a 
large  flow  of  milk  during  the  lactation  period. 

The  method  taking  the  place  of  stripping,  there  is  no  loss  of  time 
in  performing  it. 

The  use  of  the  method  develops  the  milk-yield  of  heifers,  and  has 
even  doubled  that  of  cows  which  have  been  supposed  to  have  reached 
their  maximum  flow  of  milk.     It  increases  the  fat  in  the  milk  so  that 


Univ.  Wis.  Agric.  Sta.  Boll,  No.  96. 


342 


CLEAN  MILK 


the  yield  from  this  method  contains  ten  per  cent,  of  fat.     It  is  of  great 
value  in  preventing  mastitis  during  the  early  period  of  lactation. 

As  the  method  has  been  adopted  by  some  of  the  most  progressive 
farmers  in  Denmark  and  this  country,  it  is  well  worthy  of  trial  and  is 
herewith  described. 

DESCRIPTION   OF   THE    MANIPULATIONS    IN   THE     HEGELUND     METHOD 
OP   MILKING. 

First  Manipulation. — The  right  quarters  of  the  udder  are  pressed 
against  each  other  (if  the  udder  is  very  large,  only  one-quarter  at  a 
time  is  taken)  with  the  left  hand  on  the  hind  quarter  and  the  right 
hand  in  front  on  the  fore  quarter,  the  thumbs  being  placed  on  the  out- 
side of  the  udder  and  the  four  fingers  in  the  division  between  the  two 
halves  of  the  udder.  The  hands  are  now  pressed  toward  each  other 
and  at  the  same  time  lifted  toward  the  body  of  the  cow.  This  press- 
ing and  lifting  is  repeated  three  times,  the  milk  collected  in  the  milk 
cistern  is  then  milked  out,  and  the  manipulation  repeated  until  no 
more  milk  is  obtained  in  this  way,  when  the  left  quarters  are  treated 
in  the  same  manner.      (See  Fig.  100,  Figs,  i  and  2.) 

Second  Manipulation. — The  glands  are  pressed  together  from  the 
side.  The  fore  quarters  are  milked  each  by  itself  by  placing  one  hand, 
with  fingers  spread,  on  the  outside  of  the  quarter  and  the  other  hand 
in  the  division  between  the  right  and  left  fore  quarters  :  the  hands 
are  pressed  against  each  other  and  the  teat  then  milked.  When  no 
more  milk  is  obtained  by  this  manipulation,  the  hind  quarters  are 
milked  by  placing  a  hand  on  the  outside  of  each  quarter,  likewise  with 
fingers  spread  and  turned  upward,  but  with  the  thumb  just  in  front 
of  the  hind  quarter.  The  hands  are  lifted  and  grasp  into  the  gland 
from  behind  and  from  the  side,  after  which  they  are  lowered  to  draw 
the  milk.  The  manipulation  is  repeated  until  no  more  milk  is  obtained. 
(See  Fig.  100,  Figs.  3-5.) 

Third  Manipulation. — The  fore  teats  are  grasped  with  partly  closed 
hands  and  lifted  with  a  push  toward  the  body  of  the  cow,  both  at  the 
same  time,  by  which  method  the  glands  are  pressed  between  the  hands 
and  the  body  ;  the  milk  is  drawn  after  each  three  pushes.  When  the 
fore  teats  are  emptied,  the  hind  teats  are  milked  in  the  same  manner. 
(See  Fig.  100,  Fig.  6.) 


STANDARDIZING  MILK 


343 


Standardizing    Milk 

It  may  be  desirable  to  produce  a  milk  standardized  to  contain  a 
fixed  and  constant  percentage  of  fat.  This  is  particularly  important 
for  infant  feeding.  Or  one  may  wish  to  supply  a  milk  of  unusual  and 
definite  richness  ;  or  again  one  may  want  to  combine  two  lots  of  cream 
of  different  fat  percentages  to  obtain  a  cream  of  definite  percentage. 

A  very  simple  method  of  determining  what  amount  of  any  given 
two  lots  of  milk  or  cream,  varying  in  richness,  is  required  for  combina- 
tion to  obtain  a  milk  or  cream  of  definite  fat  percentage  is  given 
below.  This  method  of  standardizing  milk  was  devised  by  Prof. 
R.  A.  Pearson,  of  Cornell  University. 

One  should  construct  a  figure  like  the  accompanying  cut,  and  in  the 


two  left  hand  corners  write  the  percentages  of  fat  in  the  two  lots  of 
milk  (or  cream  and  milk,  or  two  lots  of  cream,  as  the  case  may  be). 

In  the  centre,  place  the  percentage  of  fat  required.  At  the  right 
hand  corners  write  numbers  which  will  be  the  differences  between  two 
numbers  with  which  they  stand  in  line. 

Thus:  If  4.7  and  3.4  are  the  percentages  of  fat  in  two  lots  of 
milk — and  it  is  desired  to  make  a  mixture  containing  four  per  cent,  of 
fat — subtract  4  from  4.7  and  place  the  result  (.7)  at  the  lower  right 
hand  corner.  Subtract  3.4  from  4  and  place  the  result  (.6)  at  the 
upper  right  hand  corner. 

The  result  shows  that  it  will  take  six  parts  of  4.7  per  cent,  milk, 
and  seven  parts  of  3.4  per  cent,  milk,  to  make  a  standard  four  per 
cent.  milk. 


344 


CLEAN  MILK 


Method  of  Keeping  Accounts  of  a  Pure  Milk  Dairy 

(See  the  following  three  forms. .) 


MAPLEWOOD  FARM 
Daily  Milk  Report 

Empty  cases  received  last  trail 
Bottles  short  last  train      .      . 
Bottles  broken  when  received 
Bottles  broken  at  farm     .     . 
Cases  milk  shipped  to-day    . 


[908 


.and. 


•  Qts. 


v  The  foregoing  report  is  signed  by  the  manager  at  the  farm.  It 
shows  the  number  of  empty  cases  (holding  1 2  quart  bottles)  received 
from  the  city  and  the  number  of  bottles  broken  and  missing  in  them. 
Also  the  number  of  full  cases  shipped  to  the  city. 


II 


Driver. . . . 
Route  No. 


MILK  RECEIVED 

CASH  ACCOUNT 

Received  from 

Milk                              Cre. 
Quarts         Gals.  Pints 

iin 

.Ry 

Pints 

Paid  on  Account 

$ 

DELIVERED 

Milk 

Quarts 

Pints 

1^  Pints 

Paid  for  Tickets 

$ 

Returned 

Milk 

Quarts 

Cream 



Bottles  returned 

Total | 

This  blank  is  filled  out  daily  by  the  driver  of  each  delivery  wagon 

and  represents,  first,  the  amount  of  milk  and  cream  received  from 

railway;  second,  the  amount  of  milk  and  cream  delivered  to  customers  ; 
third,  the  amount  of  the  same  brought  back  to  the  store  ;  fourth,  the 
bottles  delivered  to  and  returned  to  customers  ;  and  fifth,  the  cash, 
paid  for  accounts  due  or  tickets. 


METHOD  OF  KEEPING  ACCOUNTS 
III. 


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This  form  represents  a  loose  card,  one  of  which  is  devoted  to  each 
customer  for  a  year.  The  day's  sales  of  the  drivers  of  the  milk 
-wagons  are  copied  off  their  books  each  day  and  kept  in  the  office  of 
the  city  dairy  in  this  form. 


346  CLEAN  MILK 


Practical    Disinfection* 

The  premises  occupied  by  animals  suffering  from  contagious 
diseases,  together  with  all  articles  contained  therein,  such  as  harness, 
blankets,  stable  implements,  and  evacuations,  must  be  disinfected  after 
the  removal  of  all  animals  and  isolation  of  the  sick.  The  excreta, 
excrement  and  urine  should  be  mixed  with  milk  of  lime  (one  part  of 
freshly  slacked  quicklime  with  two  parts,  by  volume,  of  water),  or 
with  pure  chlorinated  lime.  The  floors  and  walls  must  be  scraped 
and  washed.  Boiling  water  should  then  be  poured  over  ever}'-  avail- 
able part  of  the  premises,  and  these  brushed  with  a  saturated  solution 
of  chlorinated  lime.  Or  all  available  parts  of  infected  stables  should 
be  saturated  with  one  of  the  following  solutions  by  means  of  a  small 
hand  force-pump  or  brush  :  5  per  cent,  formalin,  2  per  cent,  cresol, 
1  to  500  corrosive  sublimate,  or  5  per  cent,  crude  carbolic  acid 
solution. 

Clothing  may  be  treated  by  boiling  in  water,  or  by  soaking  in 
a  solution  of  corrosive  sublimate  (1-500),  or  carbolic  acid  (1-20),  for 
twelve  hours.  Harness  is  disinfected  by  washing  with  soap  and 
water  and  then  with  a  2  percent,  carbolic  acid  or  creolin,  or  1-1000 
corrosive  solution.  Valueless  articles  are  given  to  the  flames.  Stable 
and  metallic  instruments  and  fixtures  are  to  be  freed  from  dirt, 
scrubbed  with  soap  and  hot  water,  drenched  with  boiling  water,  and 
then  with  a  5  per  cent,  crude  carbolic  acid  or  creolin  solution. 

Gaseous  disinfection  is  now  in  order  to  kill  micro-organisms  in 
remote  and  inaccessible  places.  This  is  frequently  out  of  the  question, 
however,  on  account  of  the  size  or  open  character  of  the  stable.  L,ive 
steam  is  the  most  efficient  means  at  our  disposal  for  this  purpose, 
when  a  suitable  apparatus  for  its  application  to  woodwork,  haymows, 
etc.,  is  obtainable.  In  place  of  this  we  may  resort  to  formaldehyde, 
chlorine  or  sulphurous  acid  gas.  In  using  formaldehyde  all  openings 
into  the  outer  air  should  be  closed  as  far  as  possible.  Then  \62/i 
ounces  of  potassium  permanganate  should  be  added  to  each  20 
ounces  of  formalin  (or  in  this  proportion)  in  deep  tin  vessels  to  avoid 
the  effects  of  frothing.      This  quantity   of  formalin    and    potassium 


*  Winslow's  Veterinary  Materia  Medica  and  Therapeutics. 


THE   TUBERCULIN   TEST  347 

permanganate  is  necessary  to  disinfect  each  1,000  cubic  feet  of 
air  space.  The  premises  should  be  closed  for  six  hours  and  then  well 
aired. 

The  walls  are  finally  painted  or  covered  with  whitewash  contain- 
ing five  per  cent,  of  crude  carbolic  acid.  Healthy  animals,  which 
have  not  been  exposed  to  infection,  may  now  be  allowed  to  return  to 
their  disinfected  quarters. 

The  Tuberculin   Test*      % 

It  is  best  to  take  the  temperature  of  the  animal  from  6  a.m.  every 
two  hours  until  tuberculin  is  injected  on  the  evening  of  the  same  day 
between  8  and  10  p.m.  The  temperature  is  taken  with  a  clinical 
thermometer  (sold  by  druggists),  which  is  anointed  with  vaseline  and 
held  in  the  rectum,  or  bowel,  for  three  minutes.  The  test  is  unreliable 
in  animals  whose  temperature  reaches  103  deg.  F.  (except  in  the 
young,  when  this  may  be  considered  a  normal  maximum)  during  the 
period  prior  to  the  injection.  Sometimes  the  test  is  not  positive  in 
animals  in  an  advanced  stage  of  tuberculosis,  but  in  these  signs  are 
often  evident,  as  emaciation,  cough,  enlarged  glands,  etc.  The  test  is 
also  misleading  if  performed  within  a  few  days  of  calving — either 
before  or  after.  The  injection  is  made  under  the  skin  just  behind  the 
left  shoulder  blade,  or  on  the  side  of  the  neck,  with  a  syringe  and 
needle  previously  boiled  for  five  minutes.  If  a  number  of  cows  are  to 
be  tested,  the  needle  and  syringe  need  not  be  boiled  before  each 
injection  is  made,  but  the  needle  should  be  wiped  off  after  each 
injection  with  a  clean  cloth  saturated  with  alcohol.  The  animal 
should  be  kept  in  the  barn  at  rest  during  the  days  of  the  test  and 
should  not  be  allowed  large  quantities  of  cold  water  to  drink  so  as  to 
reduce  the  temperature.  The  temperature  of  the  animal  should  be 
taken  at  6  o'clock  in  the  morning  following  the  injection,  and  from 
that  time  every  two  hours  till  8  p.m. 

A  rise  of  two  degrees  or  more  is  necessary  for  a  positive  reaction 
— that  is,  a  rise  of  two  degrees  over  the  maximum  temperature 
taken  the  previous  day  before  the  injection — in  order  to  prove  the 
animal  has  tuberculosis. 


*  Winslow's  "Veterinary  Materia  Medica  and  Therapeutics.' 


348  CLEAN  MILK 

Those  animals  in  which  the  temperature  does  not  rise  to  103  deg. 
F.  within  fifteen,  or  at  most  twenty,  hours  after  the  injection,  may  be 
considered  free  from  tuberculosis.  When  the  temperature  is  between 
103  deg.  and  103.8  deg.  the  test  is  doubtful,  and  the  animals  should  be 
re-tested  after  three  months. 

When  the  temperature  rises  gradually  to  103.8  deg.  F.,  or  over, 
within  fifteen  hours  after  the  injection,  the  animals  may  be  considered 
positively  affected  with  tuberculosis,  providing  this  constitutes  a  rise 
of  two  degrees  over  the  maximum  temperature  recorded  before  the 
injection. 

Before  admitting  newly  acquired  cows  to  a  herd  they  should  be 
kept  by  themselves  until  tested  twice  with  tuberculin  without  re- 
acting. This  is  necessary  because  cows  may  not  react  in  the  early 
stage  and  because  previous  treatment  with  tuberculin  may  prevent 
tuberculous  cows  from  reacting.  Therefore,  after  a  first  negative 
test  the  cows  are  kept  by  themselves  for  three  months,  when  a  second 
test  is  made  with  three  times  the  ordinary  dose.  Milk  may  be  sold  as 
certified  from  these  animals,  however,  after  the  first  test  with  a 
negative  result.  This  is  the  rule  :  in  re-tests  three  times  the  usual 
dose  is  injected,  and  in  old  and  emaciated  animals  double  the  ordinary 
amount  is  used. 

The  average  dose  of  tuberculin,  as  prepared  and  diluted  for 
immediate  use  by  the  U.  S.  Government,  is  2  c.c,  or  about  one-half 
dram,  representing  0.25  c.c.  of  pure,  old  tuberculin.  1  to  1.5  c.c. 
may  be  given  to  yearlings  and  two-year-olds,  according  to  size,  and 
bulls  and  large  animals  may  receive  3  c.c.  of  tuberculin.  Tuberculin 
should  be  kept  in  a  cool,  dark  place  and  be  rejected  if  it  becomes 
cloudy.  While  testing  cattle  may  be  done  by  the  laity,  it  had  much 
better  be  done  by  a  competent  veterinary  surgeon,  as  there  are  many 
exceptional  cases  which  can  in  no  way  be  properly  interpreted  by 
the  layman. 


BACTERIOLOGICAL  EXAMINATIONS  349 

Bacteriological  Examinations 

Dr.  Slack  writes  as  follows: 

"  We  centrifugalize  the  milk  in  small  glass  tubes  (about  2  c.c.  each, 
the  ends  being  closed  with  rubber  stoppers).  Our  apparatus  carries 
20  tubes  and  we  centrifugalize  for  ten  minutes  at  a  speed  of  2000- 
3000  revolutions  a  minute. 

"  The  sediment  obtained  on  the  rubber  stopper  is  smeared  evenly 
with  a  drop  of  sterile  water  over  a  space  4  sq.  cm.  By  examining  this 
sediment  with  a  1-12  oil  immersion  lens,  we  determine  the  presence 
of  pus  or  streptococci  and  are  also  able  to  make  a  microscopic  estimate 
of  the  number  of  bacteria  present." 

Since  it  is  impossible  to  differentiate  between  dead  leucocytes  and 
pus,  and  since  a  certain  number  of  leucocytes  are  normal  (3  or  4  in 
a  1-12  immersion  lens  field)  in  milk,  it  is  necessary  to  fix  an  arbitrary 
standard  not  to  be  exceeded  by  these  cells.  The  standard,  observed 
jby  the  Boston  Board  of  Health,  is  50  cells  to  the  field  of  a  1-12  oil 
immersion  lens  (spreading  the  sediment  from  2  c.c.  of  milk  over  a 
surface  of  4  sq.  cm.).  If  this  number  is  exceeded  the  milk  is  con- 
demned. After  the  milk  is  centrifuged  in  small  glass  tubes  (see  above), 
the  sediment  is  placed  on  spaced,  glass  slides,  dried  with  gentle  heat 
and  stained  with  methylene  blue.  During  the  course  of  the  microscopic 
examination  for  pus,  the  number  of  bacteria  can  be  determined  with 
a  very  fair  degree  of  accuracy  without  plating  the  milk  if  the  milk 
contains  more  than  100,000  bacteria  in  1  c.c. 

Milk  is  condemned  by  the  Boston  Board  of  Health  for  streptococci 
when  3  tests  are  positive:  1.  When  the  centrifuged  sediment  shows 
streptococci,  cocci  or  diplococci.  2.  When  the  plate  from  the  same 
sample  shows  colonies  resembling  streptococci  colonies,  in  excess  of 
100,000  to  1  c.c.  3.  When  such  colonies  transfe'rred  to  broth  and 
grown  for  24  hours  at  37  °  C.  show  streptococci  alone  or  in  great  ex- 
cess of  the  other  bacteria  present. 

"  The  examination  of  milk  for  pus  was  first  suggested  by  Dr. 
Stokes  of  Baltimore,  and  has  since  been  carried  out  in  a  number  of 
public  health  laboratories  in  different  parts  of  the  United  States.  The 
researches  of  Stokes,  Bergey,  Stewart,  Doane,  Slack  and  others  have 


35°  CLEAN  MILK 

shown  that  cells  are  present  in  practically  all  samples  of  milk  and  that 
in  some  samples  the  cellular  content  is  much  higher  than  is  usual. 
Where  the  number  of  cells  is  high  it  is  customary  to  regard  them  as 
pus  cells,  but  there  is  no  general  agreement  as  to  where  the  line  should 
be  drawn.  The  question  is  a  difficult  one.  because  pus  cells  and  dead 
leucocytes  are  morphologically  the  same  and  so  cannot  be  differen- 
tiated by  their  appearance  alone.  Doane  has  proposed  that  milk  shall 
be  regarded  as  containing  pus  if  there  is  high  cellular  content  accom- 
panied by  threads  of  fibrin.  Bergey  proposes  that  pus  shall  be  diag- 
nosed if  there  are  10  cells  to  the  field  of  the  1-12  immersion  lens. 
Stewart  centrifuges  1  c.c.  of  milk  in  small  tubes  and  if  he  find  23  cells 
to  the  field  of  the  1-12  immersion  lens,  when  the  sediment  of  this 
amount  of  milk  is  spread  over  1  square  cm.,  he  reports  pus.  Slack 
proposes  that  the  sediment  of  2  c.c.  milk  shall  be  spread  over  4  square 
cm.  and  that  pus  shall  be  reported  if  50  cells  are  seen  to  the  1-12  im- 
mersion field. 

"  Since  there  is  much  doubt,  in  many  cases,  as  to  whether  high 
cellular  content  actually  denotes  pus, — that  is,  as  to  whether  the  cells 
found  are  pus  cells  or  leucocytes, — and  as  to  whether  the  cells  them- 
selves are  injurious,  it  would  appear  to  be  desirable,  for  the  present, 
to  report  pus  only  where  there  is  high  cellular  content,  as  judged  by 
one  of  the  above  methods,  accompanied  by  the  presence  of  strepto- 
cocci."— Leonard  Pearson,  in  Jensen's  "  Milk  Hygiene." 

"It  is  evident  that  the  whole  subject  is  far  from  being  on  a  satis- 
factory basis.  The  various  methods  advocated  give  varying  results 
even  on  the  same  milk  sample.  Preheating  of  the  milk  to  a  high 
temperature  and  also  the  height  of  temperature  reached  in  such  pre- 
heating affect  the  result  even  when  the  same  method  is  used.  If  a 
specific  maximum  count  is  to  be  established  as  a  limit,  the  specifications 
must  therefore  include  exact  details  of  method,  temperature  and  tech- 
nique, to  secure  consistent  and  comparable  results  at  the  hands  of 
different  workers  under  different  conditions.  No  such  standard  has 
yet  been  agreed  upon.  Moreover,  normal  cows  sometimes  give  very 
exceptionally  high  counts  and  this  fact  adds  to  the  difficulties  in  de-( 
termining  an  absolute  standard." — W.  H.  Hill. 


FOOD  REQUIREMENTS  351 

Food  Requirements 

Instead  of  basing  the  feeding  standard  on  the  amount  and  propor- 
tion of  digestible  nutrients  (nutritive  ratio),  which  is  still  the  prevalent 
custom,  a  more  scientific  and  trustworthy  feeding  standard  is  based 
on  the  amount  of  digestible  protein  in  the  ration  and  the  chemical 
energy  or  fuel  value  of  the  nutrients.  The  body  may  be  likened  to  a 
machine  and  the  protein  is  necessary  for  the  repair  of  the  machine  and 
to  supply  additions  to  the  machine,  as  in  growing  animals,  and  in 
pregnant  animals,  and  in  those  giving  products  rich  in  protein — as 
milk.  Therefore,  there  is  a  standard  for  maintenance  and  another  for 
growing  animals  and  another  for  milch  cows,  etc. 

Animals  at  work  do  not  require  more  protein  than  those  at  rest, 
as  the  machine  is  running  all  the  time  and  requires  repairs  in  either 
case,  but  more  fuel  is  required.  The  carbohydrates  and  fat  represent 
the  fuel,  which  is  burned  in  the  body  to  create  heat  or  chemical  energy, 
and  runs  the  machine.  It  is  true  proteids  in  excess  or  as  waste  pro- 
ducts also  act  as  fuel,  but  being  much  more  expensive  than  carbo- 
hydrates or  fat  are  not  desirable  for  fuel.  Now  the  units  of  heat  value 
for  food  are  termed  the  calorie  (or  great  calorie)  and  therm.  The 
calorie  is  that  amount  of  heat  necessary  to  raise  I  kilogram  (2.2  lbs) 
of  water  1  degree  centigrade.  The  therm  is  equal  to  the  quantity  of 
heat  required  to  raise  1,000  kilograms  (2,204.6  lbs.)  of  water  i°  C. 
It  is  comparatively  easy  to  estimate  the  heat  value  of  food  by  burning 
it  outside  the  body  but  it  takes  very  elaborate  experiments  on  animals 
to  determine  the  heat  or  energy  value  in  the  body.  As  the  result  of 
such  investigations  the  following  tables  *  of  the  heat  or  energy  value 
of  food  stuffs  for  the  animal  have  been  made.  By  these  experiments 
the  actual  proportion  of  the  food  which  undergoes  combustion  in  the 
body  is  estimated,  as  part  of  the  food  escapes  combustion  by  way  of 
the  bowels  and  urine,  part  of  the  energy  value  is  used  in  separating 
the  real  fuel  which  the  body  can  use  from  the  useless  portion,  and 
part  is  used  in  converting  fuel  materials  into  special  products,  as  flesh, 
and  milk. 


*  Bull.  346,  U.  S.  Agricultural  Dept. 


35: 


CLEAN  MILK 


The  new  standards  for  feeding  (which  have  been  used  for  some 
years  in  estimation  of  food  requirements  for  man)  demand:  i.  The 
proper  proportion  and  amount  of  dry  matter.  2.  Of  digestible 
protein.  3.  The  proper  energy  value  stated  in  calories  or  therms  for 
lbs.  of  live  weight  per  diem  for  maintenance,  for  growth,  fattening, 
work,  milk,  etc. 

The  nutrient  requirements  are  1  lb.  of  digestible  protein  for  each 
8  to  10  lbs.  of  carbohydrates  and  fat,  and  20  to  30  lbs.  of  dry  matter 
per  diem  for  each  adult  cow. 

It  has  been  found  that  in  milk  production,  for  each  pound  of  milk 
produced,  there  is  required  (in  addition  to  the  requirements  for  main- 
tenance) 0.3  therm  in  energy  value  in  the  food  and  0.05  pound  of 
digestible  protein.    Now  to  put  this  knowledge  into  use. 

TABLE  I. 
Maintenance  requirements  of  cattle  and  horses,  per  day  and  head. 


Cattle. 

Horses. 

Live  weight. 

Digestible 

Energy 

Digestible 

Energy 

protein. 

value 

protein. 

value. 

Pounds. 

Pounds. 

Therms. 

Pounds. 

Therms. 

150 

O.I5 

1.70 

0.30 

2.00^ 

250 

.10 

2.40 

.40 

2.80 

500 

•30 

3.80 

.60 

4.40 

75o 

.40 

4-95 

.80 

5-8o 

1,000 

•50 

6.00 

1. 00 

7.00 

1.250 

.60 

7.00 

1.20 

8.15 

1,500 

•65 

7.90 

1.30 

9.20 

FOOD  REQUIREMENTS 


353 


TABLE  II. 

Dry  matter,  digestible  protein,  and  energy  values  per  ioo  pounds. 


Feeding  stuff. 


Green  fodder  and  silage  : 

Alfalfa 

Clover — crimson 

Clover — red 

Corn  fodder — green 

Corn  silage 

Hungarian  grass 

Rape 

Rye 

Timothy 

Hay  and  dry  coarse  fodders  : 

Alfalfa  hay 

Clover  hay — red  ......... 

Corn  forage,  field  cured. . . 

Corn  stover 

Cowpea  hay 

Hungarian  hay , 

Oat  hay 

Soy  bean  hay , 

Timothy  hay 

Straws  . 

Oat  straw 

Rye  straw , 

Wheat  straw 

Roots  and  tubers : 

Carrots    

Mangel-wurzels 

Potatoes 

Rutabagas 

Turnips 

Grains : 

Barley 

Corn 

Corn-and-cob  meal 

Oats , 

Pea  meal 

Rye 

Wheat 

By-products  : 

Brewers'  grains — dried 

Brewers'  grains — wet , 

Buckwheat  middlings   

Cotton-seed  meal 

Distillers'  grains — dried — 

Principally  corn 

Principally  rye 

Gluten  feed — dry 

Gluten  meal — Buffalo 

Gluten  meal — Chicago 

Linseed  meal — old  process. 

Linseed  meal — new  process 

Malt  sprouts 

Rye  bran 

Sugar-beet  pulp — fresh 

Sugar-beet  pulp— dried 

Wheat  bran 

Wheat  middlings 


Total  dry 

Digestible 

Energy 

matter. 

Protein. 

value. 

Pound?. 

Pounds. 

Therms. 

28.2 

2.50 

12.45 

19. 1 

2.19 

11.30 

29.2 

2.21 

16. 17 

20.7 

.41 

12.44 

25.6 

1. 21 

16.56 

28.9 

i-33 

14.76 

14.3 

2.16 

11   43 

23-4 

1.44 

11.63 

38-4 

1 .04 

19.08 

91.6 

6-93 

34-4r 

84.7 

5.41 

34-74 

57.8 

2\$ 

3°-53 

59-5 

1.80 

26.53 

89.3 

8.57 

42.76 

92-3 

3.00 

44  03 

84.0 

2-59 

36.97 

88.7 

7.68 

38.65 
33-  56 

86.8 

2.05 

90.8 

1.09 

21.21 

92.9 

•63 

20.87 

90.4 

•37 

16.56 

n. 4 

•37 

7.82 

9.1 

•14 

4.62 

21. 1 

•45 

18.05 

11. 4 

.88 

8.00 

9.4 

.22 

5-74 

89.1 

8-37 

80.75 

89.1 

6.79 

88.84 

84.9 

4-53 

72.05 

89.0 

8.36 

66.27 

|9S 

16.77 

71-75 

88.4 

8.12 

81.72 

89.5 

8.90 

82.63; 

92.0 

19.04 

60.01 

24-3 

3.81 

14.82 

88.2 

22.34 

75-92 

91.8 

35'5 

84.20 

93-° 

21  93 

79- 23 

93-2 

10.38 

60.93 

91.9 
91.8 

19.95 
21.56 

79-32 
88.80 

90.5 
90.8 

33 -°9 

78.49 

27-54 

78.92 

90. 1 

29.26 

74-67 

89.8 

12.36 

46.33 

88.2 

i'-35 

56.65 

10. 1 

•63 

7-77 

93-6 
88.1 

6.  So 

60. 10 

10.21 

48.23 

84.0 

12.79 

77.65 

54 


CLEAN  MILK 


Supposing  that  we  wish  to  determine  a  standard  for  feeding  a  herd 
of  cows,  each  weighing  on  the  average  850  lbs.  and  yielding  on  the 
average  25  lbs.  of  milk  each  daily : — 

We  first  consult  Table  I  for  standards  for  maintenance  of  cattle. 
We  find  that  for  cattle  weighing  850  lbs.  the  daily  requirements  are  : — 

Digestible  protein.  Energy  value. 
Lbs.  Therms. 

For  maintenance 0-45  5-6 

For  25  lbs.  of  milk 1.25  7.5 

1.7.0  13.  to 

For  cows  giving  25  lbs.  of  milk  we  find  that  we  must  add  to  the 
maintenance  figures  the  required  energy  value  in  therms  corresponding 
to  this  milk  yield.  It  was  stated  above  that  for  each  pound  of  milk 
yield  there  will  be  required  0.3  therm  of  energy  value  and  an  allowance 
of  0.05  lb.  of  digestible  protein.  Therefore,  multiplying  each  of  these 
factors  by  25,  and  adding  the  results  to  the  required  standard  in  di- 
gestible protein  and  therms  for  maintenance,  we  get  the  standard  re- 
quired for  cows  weighing  850  lbs.  and  giving  daily  25  lbs.  of  milk,  as 
.above. 

Next  we  desire  to  so  arrange  the  various  food  stuffs  at  command 
that  the  proper  proportion  of  dry  matter  and  proteids  are  attained  and, 
especially,  that  the  nutrients  in  the  aggregate  furnish  the  amount  of 
digestible  protein  and  energy  value  required  by  our  standard  above.  '■ 

We  have  found  that  there  should  be  20-30  lbs.  of  dry  matter  in  a 
daily  ration  and  at  least  1  lb.  of  digestible  protein  for  each  8  to  10 
lbs.  of  the  other  nutrients  (fat  and  carbohydrates). 

We  must  first  concoct  a  theoretical  ration  from  the  food  stuffs 
at  hand  and  then  alter  the  ration  to  accord  with  the  standard,  or  to 
substitute  one  food  stuff  for  another  on  account  of  greater  economy. 

We  will  select  the  first  ration  on  p.  72  consisting  of  20  lbs.  of 
timothy,  2  lbs.  of  oats,  4  lbs.  of  gluten  meal  and  4  lbs.  of  wheat 
bran. 

Consulting  Table  II,  showing  dry  matter,  digestible  protein  and 
energy  value  per  100  lbs.,  we  find  that  each  of  the  food  stuffs  selected 
contain  of  these,  as  will  be  seen  below : 

Protein,  lbs. 

Timothy,  20  lbs .41 

<  >ats,  2  lbs .17 

Bran,  4  lbs .04 

Gluten,  4  lbs .08 

Total 1.78  13.13  26.3 


rherms. 

Dry 

matter. 

6.71 

'7-3 

i-33 

1.8 

1.92 

3-5 

3-i7 

3-7 

TYPHOID  FEVER  CASE  CARD  355 

The  result  will  be  seen  to  correspond  almost  precisely  with  the  standard 
in  energy  value  and  dry,  digestible  protein. 

These  results  are  arrived  at  by  multiplying  the  number  of  pounds 
of  each  of  the  food  stuffs  selected  by  the  percentage  of  dry  matter, 
digestible  protein  and  therms  in  one  lb.,  as  shown  in  the  table. 

Thus,  20  lbs.  of  timothy  :  Timothy  contains  86.8  lbs.  of  dry  matter 
in  each  100  lbs.  One  pound,  therefore,- contains  .868  X  20  =  17.36  of 
dry  matter,  and  so  on  with  the  protein  and  therms  required. 

If  this  ration  did  not  fulfil  the  standard  requirements,  as.  for 
instance,  if  the  gluten  were  left  out  or  if  we  wished  to  substitute  one  ot 
the  food  stuffs  by  a  cheaper  one,  we  would  only  have  to  experiment  by 
adding  more  or  less  of  the  other  food  stuffs,  or  using  another  food 
stuff  richer  or  poorer  in  food  requirements. 


Typhoid  Fever  Case  Card* 

Date  of  investigation Case  No 

Name 

Age Color Sex Nationality 

Probable  date  of  onset Date  of  definite  symptoms 

Name  and  address  of  physician  :     

Residence 

Residence  in  D.  C 

Residence  when  taken  sick from to 

Previous  residences t ...  from to 

Subsequent  residences from to 

Temporary  absences  from  D.  C.  within  30  days  prior 

Number  of  occupants Ages 

"  "  who  have  had  typhoid When  ? 

Newcomers  in  house  within  three  months  prior 

"  "         had  typhoid  ? 

Servants — 

White:     Resident Typhoid?. 

Non-resident Typhoid  ? . 

Colored  :  Resident Typhoid  ?. 

Non-resident Typhoid  ? . 

Typhoid  at  home  of  servants When  ? 

Disposal  of  sewage W.  C.  in  house.  .  , 


*  Public  Health  and  Marine  Hospital  Service — Hygienic  Laboratory. 


356  CLEAN  MILK 

"W.  C.  in  yard Privy Location 

General  sanitary  condition  of  residence 

OCCUPATION. 

Place from to 

Other  cases 

WATER   WITHIN   30  DAYS   PRIOR. 

Solely Principally 

Occasionally 

FOOD  WITHIN  30  DAYS   PRIOR. 

Where  taken 

Milk  (how  used) From 

Boiled  ? Pasteurized  ? 

Ice  cream  ? Where  ? 

Uncooked  fruits  and  vegetables 

Shellfish 

CONTACTS. 

Association  30  days  prior  with  patients  in  febrile  stage 

"  with  suspected  cases 

"  with  persons  who  have  had  typhoid  within  6  months 

1  year 

2  years 

3  years 

4  years 

5  years 

Association  30  days  prior  with    persons  in  contact  with  patients  in    febrile 

stage 

Treatment  of  stools  and  urine  of  patients 

Other  precautions 

Remarks 

Summary 

Signature 


IDENTIFYING  COWS 


357 


_|»    O 

o      » 


•n  o  5 


■nolg 


INDEX 


Page 
Acidity  of  milk,  test  for 19° 

of  pasteurized  milk 190 

Actinomycosis  affecting  milk.  .. .     33 

of  udder 33 

Agar,  plain  nutrient 273,  2S3-4 

Air  space  required  by  cows 80 

Albumin  of  milk 43 

Aseptic  milk  301 

Ash  of  miik 43,  46 

Ayrshire  cows 313 

Artificial  milk 269 

Babcock  test  for  milk  fat 193 

Bacilli  acidi  lactici...2o,  21,  23,  44,  296 

colon 21,  40,  278,  304 

fcetidus  lactis 27 

lactis  aerogenes.  .21,  202,  297,  300 

lactis  viscosus 28 

tuberculosis.  .29,  30,  40,  95-97,  276 
Bacteria,  action   on    buttermilk, 
cream,    cheese    and    con- 
densed milk 2 

action  of  temperature  on. 4-16,  302 

analysis  of  in  milk 24 1,  307-9 

apparatus  required 278 

controls  in 25S 

counting  in 260 

dilutions  for 254 

Gram's  stain  in 277 

incubation  in 259 

media  making  for.  .256,  262  72 
reaction  of  media  for. .  .  .  287 

uses  of  media  for 272 

plating  in 256 

technique  of 257 

simple  stain  for 275,  295 

standard  methods  for. . . .  264 

atmosphere  suitable  for 239 

capsules  of 236 

causing  flavor  of  butter 58 

359 


Page 

Bacteria,  characters  of 3,  233,  298 

classification  of.  .  .40,  41,  237,  281 
conditions  of  growth  of, 

4-8,  25,27,  239. 

darkness  requisite  for 240 

essentials  for  life  of. 238 

food  of 239 

higher 23S 

humidity  required 240 

identification,  standard  meth- 
ods   240,  282 

in  barn 77,  93 

in  butter 309 

in  buttermilk 309 

in  cheese 96,  311 

in  cold  storage 4,  5 

in  cream 56,  58.  142,  309 

in  filtered  milk 56,  57,  106 

in  fore  milk 48,  304 

in  frozen  milk 4 

ingrain 303 

in  hay 77,  303 

in  ice  cream    38 

in  manure 304 

in  market  milk 26 

in  milk,  classification  of, 

40,  4r,  237,  281 

bottles 303 

utensils 304 

in  separated  cream 56,  142 

in  set  cream 58,  142 

influence  on  milk  and  pro- 
ducts       19 

lactic  acid 20,  21,  44,  296 

action  on  man 20 

flavoring      butter       and 

cheese 20 

liquefying 23.  24,  77,  299 

miscellaneous 23,  307,  311 

flavoring  butter 58 


;6o 


INDEX 


Page 

Bacteria,  moisture  affecting 6 

multiplication  of 4-6 

number  in  clean  milk 25 

in  air 302 

of  butyric  acid 27 

of  disease  in  milk 28-39 

of  pus  in  milk 250,  295,  349 

of  tuberculosis  in  buttermilk.     95 
in  milk.. 29,  30,  40,  95,  97,  276 

on  hair 304 

on  hands ioi,  305 

pasteurization  affecting 7,  16 

shape  of 234 

significance  of  in  milk 19,  24 

of  numbers  of  in  milk.  .19,  24 
of  quantity  and  variety  in 

milk 15,  18,  28 

of  size 234 

of  sunlight  affecting 6 

spore  bearing 4-10,  16,  77,  236 

sunlight  affecting 6 

stains  for 275,  277,  295 

standard  method  for  analysis 

of  in  milk 264 

for  identification  of 2S2 

standards  for  water  supply . .     75 

structure  of 234 

temperature  affecting. 4, 16,  23, 302 

suitable 239 

Bacterial  terms,  glossary  of 285 

Bacteriologist,  report  of 293 

form  for 231 

Bacteriology,  dairy,  experiments 

in 293 

Balanced  ration,  selection  of 73 

computing 351 

specimens  of 72,  73 

Bang  system 97 

Barn,  disinfection  of 346 

dust 72,  93,303 

floors Si 

for  milking  only 82 

inspection  of 178-1S1 

plans  of 322 

ventilation  of. 81.  90 

Barns 80,  95 

Basket,  delivery 166.  167 

Beasiings 51 

Bedding 93 

Bitter  milk 27,  28 


Page 

Black  quarter  affecting  milk 17S 

Blue  milk 27 

Bookkeeping,  city  milk  route.  16S,  344 

Borax  in  milk 188 

Bottle  boxes 138 

brushes 129 

caps 168 

carriers 137 

filler 125,  136 

paper  milk 140 

sterilizer 126-128 

washer. 129,  328 

Bottled  milk,  cooling  of 11S,  124 

Bottles,  milk 140 

paper  milk 140 

to  prevent  loss  of. 166 

Bottling  milk , 123 

utensils  for 123 

Botriomycosis  affecting  milk 33 

affecting  udder 33 

Broth,  plain  nutrient 274 

Brown  milk 27 

Brushes  for  cleaning  milk  uten- 
sils     129 

Burrell- Lawrence  milking    ma- 
chine    338 

Butter,  action  of  germs  on 2 

composition  of 63,  155 

fat,  to  pay  creamery  patrons 

for 157 

flavor 58 

from  fresh  cream 58,  61 

starters 59.  61 

making,  losses  in 155 

overrun  in 154 

milk,  composition  of. 63 

tuberculous  germs  in. 95,  96 

Bye-products  of  milk 65 

Caps  for  milk  bottles 16S 

Care  of  milk  by  consumer 163 

Carriers  for  milk  bottles 137 

Cans,  cooling 123 

milk in,  122 

stoppers  of 122 

Cars  for  milk 138 

Casease 23 

Casein 43 

computed  from  fat-content. . .  199 

in  its  relation  to  fat-content . .  199 


INDEX 


361 


Page 

Casein,  test  for 199-202 

Catalase 9 

Certified  milk,  circular  describing  219 

cost  of 151 

how  to  begin  sale  of 154,  170 

methods  and  standards 228 

New  York  requirements 219 

price  of 151 

standards  and  origin  of. 24,  25 

Cheese,  action  of  germs  on 2 

composition  of 62 

hard 62 

making 62 

ripening 62 

soft 62 

Chemist's  milk  report 230 

Cholera  affecting  milk 35 

bacilli  in  milk 40 

City  milk  supply,  inspection  of. . .  176 

Clarified  milk 56 

Classification,  bacteria  in  milk, 

40,  41,  237,  281 

Migula-Chester 281 

Cleaning  cows 98 

milk  utensils 122,  303 

Cloth  ventilation  for  barns 88 

Clothing  for  milkers 101,  102 

milk  room  employees 133 

Cohn.'s  solution 272,  275,  284 

Colon  bacilli 21,  40 

Colostrum 51,  52 

as  a  source  of  disease 52,  53 

Commercial  starters,  Farrington.59  61 

analysis  of 310 

Composite  samples  of  milk 148 

Composition  of  butter 63,  155 

butttermilk 63 

cheese 63 

colostrum 52 

cream 57,  144 

altered  by  separator 142 

human  milk 47 

milk 46-48 

affected  by  abortion 51 

excitement 50 

exposure 50 

food 47,  66 

fright 50 

milking 48 


Page 
Composition  of  milk  affected  by 

nymphomania 51 

period  of  heat 50 

period  of  lactation. . .     50 

season 49 

surroundings 50 

treatment  of  cows. . .     50 

skim  milk 46,  57 

strippings 48 

whey , 63 

Concentrated  milk 335 

Concentrates 71 

Condensed  milk,  germs  affecting.      2 

Coolers,  cream 135 

milk 113-119 

covered 119 

Star 114 

tubular 114 

Cooling  milk  and  cream 123,  306 

Cost  of  certified  milk 151 

of  producing  milk 150 

Cow,  annual  cost  of. 146,  149 

Ayrshire 313 

care  of 95 

census 146 

for  milk 313 

dairy,  characteristics  of 313 

dehorning 318 

diseases  affecting  milk  .  .29-44,  78 

grooming 98 

Guernsey 313 

Holstein 313 

inspection  of 178-180 

Jersey 313 

number  in  barn 82 

pox  affecting  milk 33 

profits 146-149 

rations 72-73'  35* 

records 148 

how  to  keep 148 

returns  from 147 

stall 91 

standard 14S 

tuberculosis  affecting  man, 

3r.  92.  96 

value  of 321 

Cream,  acidity  of  for  butter 191 

bottling 143 

composition  of 57,  142,  144 


362 


INDEX 


Page 
Cream,  conditions  favoring  rising    54 

cooler 135,  143 

dipper 172 

per  cent,  of  solids  in 57 

ripening  of 58 

separated,  germs  in 56,  142 

separation  of 143 

separator 55,  143 

set 58 

starters 59-61 

thickeners 144 

whipping 144 

Culture  media  for  bacteria.  255,  262-72 

Curdling  of  milk 20,  21 ,  44 

Curd  test 202 

Dairy,  arrangement  of 34-37 

bacteriology,  exercises  in 293 

cows 313 

inspection  of 177 

room no 

routine 131 

utensils in,  145 

washing  of 122 

Dehorning  cows 318 

Depots,  milk,  for  infants 173 

Diarrhea  caused  by  milk 32,  38 

of  cows  affecting  milk 33 

Diphtheria  affecting  milk 35 

bacilli  in  milk ,     40 

carriers 35 

Dirt  in  milk 175-6,  305 

Disease  of  cows  affecting  milk.  .29-34 

Disinfection  of  barns 346 

Distribution  of  milk 162 

Doane's  determination  of  leuco- 
cytes   295 

Drivers'  uniforms 170 

Drugs  affecting  milk 34 

Dust  from  cow 303 

in  barn 77,  93,  303 

in  hay 77,  303 

in  milk  room 133 

Dysentery  affecting  milk 33,  35 

Ensilage  affecting  milk 75 

Enzymes  in  milk 8,  n 

affected  by  pasteurization 7 

Farms,  inspection  of 178-1S1 


Page 

Farrington,  acidity  test 190 

on  starters 60 

Fat  in  relation  to  casein 199 

of  milk 45,  46 

test  in  milk  and  cream 193 

Feeding  affecting  composition  of 

milk 66,  68 

balanced  ration  for 73 

computing 35  r 

concentrates 71 

for  milk 66 

Haecker's  rules  for 71 

in  relation  to  milking 76 

of  silage 77,  93 

Lehman's  rules  for 72 

roughage 71 

salt 74 

specimen  rations 72,  73 

standard  for 69,  73 

tables  for 351-353 

Wolff's  standard  for 68 

Ferments  in  milk  .   8-n 

affected  by  pasteurization 8-n 

Feser's  lactoscope 203 

Filter,  revolving 108 

Filtering  milk 56,  57,  106,  1  iS 

Fishy  milk 74, 122 

Flies  in  barn 92 

spray  for 92 

Food,  influence  on  lactation 68 

imparting  flavor  to  milk. ...  76,  77 

imparting  taste  to  milk 76,  77 

Foot  and  mouth  disease  affecting 

milk 33 

Fore  milk 48,  304 

Formaldehyde  in  milk 188 

Freezine 17 

Galactase 9 

Garget  affecting  milk 31,  32 

Gelatine  in  milk,  test  for 192 

plain  nutrient 273,  283 

germicidal  substance  in.  .5,  9,  301 
Germs,  see  Bacteria. 

Globulin  in  milk 43.  44 

Glossary  of  bacterial  terms 285 

Gram  stain 277 

Green  milk 27 

Grooming  cows 98 

Guernsey  cows 313 


INDEX 


363 


Page 
Gutters  for  manure 94 

Haecker's  feeding  rules 71 

Hart  casein  test 200 

Hay  dust 77 

Heating  water  for  dairy 120 

Hegelund   method    of  stripping 
cows 341 

Holsteiu  cows 313 

Home  pasteurization 13 

Human  milk,  composition  of ... .    47 

Iceline 17 

Ice  cream,  germs  in 38 

Indentification  of  bacteria 282 

Indol,  test  for 271 

Infant  feeding,  milk  for 170-73 

Infant  milk  depots 173 

Infant  mortality 38-9 

Inspected  milk 225 

Inspection  of  milk 1 74 

by  bacteriologist 231 

by  chemist 230 

of  dairies.  ...177,  183,  184,211,214 

of  dairy  farms 178-181 

employees 229,  231 

of  city  dairies,  177,183,184,211,214 

of  city  milk  supply 176 

of  creameries 177 

of  milk 174,  215 

of  wagons 165 

veterinary 178,  229 

Jersey  cows 313 

Keeping  qualities  of  milk 22 

King  system  of  ventilation 82-87 

Laboratory,  apparatus  for 278 

Laboratory  exercises  in  dairy  bac- 
teriology   293 

Lactation  period  of  cows 50 

increased  by  feeding 6S 

Lactic  acid  bacteria 20-25 

action  on  man 20 

in  fermentation  of  milk 44 

flavoring  butter  and  cheese. .     20 

killing  other  germs 20 

Lactokinase 9 

Lactometer 146,  197 


Page 
Lactometer,  New  York  Board  of 

Health 202 

Lactoscope,  Feser's 203 

Leucocytes,   Doane's  determina- 

nation 295,  349 

standard  for 250,  295,  349 

Lipase 9 

Liquefiers 23-24 

Litmus  milk 269,  283 

Litmus  solution 271 

Loffler's  blood  serum 270-283 

Machine,  milking 336 

Malta  fever  from  milk 35 

Manure,  removal  from  barn 91 

a  source  of  tuberculosis 30 

Market  milk,  bacteria  in 26 

Mastitis  affecting  milk 31,  32 

Mediator  milk  analyses,  256,262-72,287 

Microscopic  study  of  milk 294 

Migula-Chester  classification,  bac- 
teria   281 

Milk,  acidity  of 190 

action  of  temperature  on,  4-16,  38 

adulterated  with  borax 188 

with  boric  acid 188 

with  formaldehyde 188 

with  salicylic  acid 189 

with  sodium  carbonate . . .  188 

albumin 43 

affected  by  foods  75"79 

by  drugs 34 

as  a  source  of : 

cholera 35 

diarrhea  32,  ^2,  38 

diphtheria.. 32,  35,  37 

dysentery 35 

infant  mortality 37"39 

Malta  fever 35 

milk  sickness 34,  78 

scarlet  fever 32,  35,  37 

smallpox 35 

sore  throat 32 

typhoid  fever 35.  37 

tuberculosis 29,  92,  96 

aseptic 301 

ash  of 43.  46 

agar 297 

bacteria,  analysis  of 241-309 

bad  odor  of 176 


364 


INDEX 


Page 

Milk,  bad  taste  of 176 

bitter 27,  28 

bloody 32 

blue 27 

bookkeeping,  city  route.  .168,  344 

-borne  epidemics 35~37 

bottle 140 

caps 168 

carriers 137 

cars 138 

paper 140 

shipping  cases 139 

to  prevent  loss  of 166 

bottling  of 123 

utensils  for 123 

boxes  for  bottles 139 

brown 27 

bye  products  in  manufactures    65 

cans in,  122 

cooling 123 

stoppers 122 

care  of  by  consumer 163 

certified 24,  25,  170 

cost  of 151 

N.  Y.  requirements  for  . .  219 

price  of 151 

clarifying 56 

composite  samples  of 148 

composition  of. 46-48 

concentrated 335 

coolers 113-119 

covered 119 

condensed,  germs  in 2 

curdling  of. 20,  21 

depots  for  infants 173 

dipper 172 

dirt  in 175,  176,  305 

dirty,  source  of  tyrotoxicon  .     38 

distribution  of. 162 

drugs  affecting 34 

during  tuberculin  test 97 

dust  in 27,  28 

estimation  of  value 154 

fat 45.46 

test  for 193 

feeding  affecting  composition 

of. 66,  6S 

feeding  for 66,  351 

ferments  in. 8-1 1 

fever  affecting 33 


Page 

Milk  fever,  treatment  of. 98 

filtering 56,  57,  106,  118 

fishy 74,  122 

for  infant  feeding 170-173 

formation  in  udder 66 

from  silage 75 

germicidal  action  of 5,  9,  301 

green 27 

hints  in  delivery  of 162 

house,  arrangement  of...ni-i37 

plans  of 322-335 

human 47 

in  actinomycosis 33 

anthrax 33 

black  quarter 178 

botriomycosis 33,  178 

cow  pox 33 

diarrhea 33 

dysentery 33 

foot  and  mouth  disease. .     33 

garget 31.32 

mastitis 31,  32 

milk  fever 33 

milk  sickness 78 

pleuropneumonia 38 

rabies 34 

retained  afterbirth 33 

septic  metritis 33 

suppurative  conditions  . .     33 

tetanus 34 

tuberculosis 29,  30,  95-97 

umbilical  infection 33 

vaginal  discharge 29 

infection  of 35,  185 

inspected 225 

inspection 174-232 

by  bacterioiogist 231 

chemist 230 

of  barns 205,  209 

score  cards  for, 

205,  206.  209 

cars 182 

cows 178,  206 

score  cards  for, 

180,  206,  209 

farms 178-181 

score  cards  for 

180,  205-6,  209 

hotels 186 

milk  sales  rooms 212 


INDEX 


365 


Page 
Milk,  inspection  of  pasteurized  . .  216 

pastures 206 

restaurants 186 

ventilation 205 

wagons 182,  211 

veterinary 178,  229 

score  card  for 230 

water  supply 205 

"keeping  qualities  of. 22 

leucocytes  in 295 

standard  for     •  250,  296,  349 
licenses,  see  Permits. 

litmus 269 

medium . 269 

microscopic  study  of 294 

mineral  matter  in 43,  46 

mixing in,  "9 

modified 170 

pails 104-107 

pasteurized 7-16,  3°7 

tests  for 189,  216 

pasteurizers 15 

permits 204 

dairy 207 

farm 207 

milk  importer 207 

notice  revoking 179 

preservatives 17 

tests  for 188,189 

production,  cost  of 15° 

properties,  chemical 42 

physical ...    42 

vital 42 

proteids 43 

pus  in s 249,  296 

standards  for.. .  .250,  296,  349 

reaction  of 42 

records 148 

red 27 

returns 160 

ropy 27-8,  32,  176 

room in,  137 

utensils in 

routine 131 

samples i74»  J75 

collecting 251 

scarlet  fever  from 33 

secretion,  physiology  of 71 

sickness 34,  78 

siphons 172 


Page 

Milk,  skimmed,  food  value  of, 

64,  159.  l6° 

test  for 204 

slimy 27,  28,  32,  176 

soapy 27 

solids 43,  46,  197-204 

estimation  of 199 

souring  of 20,21,44 

standard  for  cow 148 

standardizing 343 

standards 25,  249 

starters 59~6x 

analysis  of 3IQ 

sterilizers. 126,  128 

stirrer 132 

strainers 118 

stringy 27,  28,  32,  176 

strippings 48 

sugar 43 

sweet 17 

curdling 33-  44 

tickets 167 

time  of  delivery ...  162 

turnip  flavor  of 77 

utensils 1 1 1-145 

washing 122 

wagons 165 

inspection  of 165 

watered,  test  for 204 

woman's 47 

yellow 27 

yield,  conditions  affecting. .  .48-51 

temperature  affecting 4-6 

Milkers,  cleanliness  of 101 

dress  of 101-102 

Milking 102 

affecting  composition  of  milk  101 

barns > 82 

in  relation  to  feeding 76 

machine 336 

period 5° 

Mineral  matter  in  milk 43,  46 

Miscellaneous  bacteria  in  milk ...     23 

Mixing  milk Hi,  119 

Modified  milk  for  infants 170 

Nitrate  broth 270 

Nitrites,  test  for 271 

Oidium  lactis 297 


366 


INDEX 


Page 

Overrun 154 

how  to  estimate 156 

Pails,  milk 104-107 

Paper  milk  bottle 140 

Paracasein 44 

Pasteurization 7-16 

affecting  ferments 8-1 1 

city  regulations  for 216 

cost  of 14 

disease  germs  affected  by  ..  .7-15 

germs  in 307 

home 13 

spores  affected  by 7-16 

Pasteurized  milk,  tests  for, 

189,  216,  307 

Pasteurizers 15 

Permits,  dairy 207 

farm 207 

milk  importer 207 

Plans  of  barns 322-333 

of  city  dairy 335 

of  dairies 324~335 

Pleuropneumonia  affecting  milk . .     33 

Potato  medium 270 

Preservatives 33 

tests  for 188-189 

Price  of  certified  milk 151 

Proteids  in  milk 43 

Pseudomonas  coli 40 

Putrefactive  germs 23,  24 

Quevenne's  lactometer 197 

Rabies  affecting  milk 34 

Reaction  of  media,  adjustment. . .  287 

Records  of  cows 314 

of  milk. 148,  320 

Red  milk 27,  28 

Retained  afterbirth  affecting  milk    33 

Roughage 71 

Rutherford  ventilating  system  ...    89 

Salicylic  acid  in  milk 189 

Salt  for  cows 74 

Sampling  milk 174,  251 

Samples,  milk,  form  for  collectors 

of 215 

Scarlet  fever  from  milk 32 

infecting  milk 35~37 


Page 

Scarlet  fever  organisms 40 

Score  cards  for  barns 205,  209 

barnyards 206 

cows 206,  209 

city  milk  plants 211,  214 

dairies 209,  214 

handling  of  milk 209 

milkers 209 

wagons 212 

Separation  of  cream 143 

removing  germs 56,  142 

dirt 56 

Separator  cream 56 

slime   55 

Separators,  management  of 321 

Serum ....  275 

Septic  metritis  affecting  milk 33 

Shipping  cases 138 

Siphon,  milk 172 

Silicate  jelly 272,  275,  284 

Skim  milk,  composition  of. 46,  57 

food  value  of 64,  159,  160 

test  for , 204 

value  of 64.  159.  160 

Slimy  milk 27,  28,  32 

Smallpox  infecting  milk 35 

Soapy  milk 27 

Sodium  carbonate  in  milk 188 

Solids  of  milk 43,  46,  48,  197-204 

test  for 199 

Sources  of  bacteria  in  milk  classi- 
fied     41 

Souring  of  milk 20,  21,  44 

Spores  in  milk 4,  7,  8,  10,  16,  77 

Stables,  disinfection  of 346 

Stalls 90 

Stanchions 90,  331 

Standardizing  milk 343 

Star  cooler 114 

Starch  jelly 275 

Starters 59,  310 

Startoline 60 

Steam  heating  tee 131 

Sterilizers 126-128 

Storch's  test 189 

Strainer  cloths 118 

Straining  milk 56,  57,  106,  118 

Streptococci 18,  31,  32,  250 

standards  for  in  milk 250,  349 

Streptococcus  lacticus 21 


INDEX 


3t>7 


Page 

Stringy  milk 27,  28,  32 

Stripping  cows,  Hegelund method  341 

Strippings  of  milk 48 

Sugar  of  milk 43 

Suppuration  affecting  milk 20 

Sweet  curdling  of  milk 33,  44 

Tail  holder 99 

Temperatures  affecting  milk. 4-16,  302 

Test  for  acidity  of  milk . .  .190-192 

for  gelatine 192 

indol 271 

nitrites 271 

pasteurized  milk 189 

preservatives 188 

pus 295,  349 

solids  in  milk 197,  203 

streptococci 250,  349 

tuberculosis 95,  347 

viscogen 192 

watered  milk 204 

Tetanus  affecting  milk 34 

Tickets,  milk 167 

Tie-ups 90,  331 

Tonsilitis  from  milk 32 

Transportation  of  cans 123 

Trembles 34,  78 

Tubercle  bacilli,  stain  for 276 

Tuberculin  test 95,  347 

Tuberculosis  affecting  cow 29,  30 

affecting  man  through  milk, 

31.  92,  96 

udder 29,  32 

bacilli  in  butter 95-96 

in  milk  . .       29,  30,  40,  95-97 

stain  for 276 

Tuberculous  cows,  dangers  of, 

31.  92,  96 

Tubular  coolers 114 

Typhoid  fever  affecting  milk .  35,  37, 40 
carriers 35 


Page 
Tyrotoxicon  in  milk 38 

Udder,  anatomy  of 48 

actinomycosis  of 33 

botriomycosis  of 33 

physiology  of 66 

tuberculosis  of 29,  32 

Umbilical  infections  infecting  milk    33 

Uschinsky's  solution 272,  275,  284 

Utensils in,  145 

cleaning 122 

in  milk  room in 

Vaginal  discharge  in  milk 30,  33 

Ventilation  of  barns 82-90 

cloth  method 88 

King  system  of 82-87 

Rutherford  system 89 

Veterinary  inspection  of  cows, 

100, 178,  229 
reports 230 

Viscogen  in  milk 144,  192 

Wagons,  milk 165 

Washing  dairy  utensils  122,  192,  303-4 

machine 328 

sink 122 

Water,  germ  standard  for 75 

for  dairy  use 37,  74-75 

heating 120 

supply 74-75 

stagnant,  in  pastures 74 

Watered  milk,  test  for 204 

Watering  cows 74 

Wells 75 

Whey,  composition  of 63 

Whipping  t:ream. 144 

Yellow  milk 27 

Ziehl-Nielsen  stain 276 


fccsw 


State  CtUe* 


CATALOGUE    OF 

William  R.  Jenkins  Co.'s 

Works   Concerning 

HORSES,  CATTLE,  SHEEP,  SWIHE,  Etc. 
1909 


(*)  Designates  New  Books. 

(t)  Designates  Recent  Publications. 


ANDERSON.  "Vice  in  the  Horse"  and  other  papers 
on  Horses  and  Riding.  By  E.  L.  Anderson.  Size, 
6x9,  cloth,  illustrated 1  75 

AB3ISTEAD.      "  The  Artistic  Anatomy  of  the  Horse." 

A  brief  description  of  the  various  Anatomical  Struc- 
tures which  may  be  distinguished  during  Life  through 
the  Skin,  By  Hugh  W.  Armstead,  M.D.,  F.R.C.S. 
With  illustrations  from  drawings  by  the  author 
Cloth  oblong,  10  x  12£ 3  75 

BACH.  "How  to  Judge  a  Horse."  A  concise  treatise 
as  to  its  Qualities  and  Soundness;  Including  Bits  and 
Bitting,  Saddles  and  Saddling,  Stable  Drainage,  Driv- 
ing One  Horse,  a  Pair,  Four-in-hand,  or  Tandem  etc 
ByCapt.  F.W.Bach.     Size,  5 x7|,  clo.,  fully  illus.l  00 

BANHAOf.  "Tables  of  Veterinary  Posology  and  Thera. 
peutics,"  with  weights,  measures,  etc.  By  Geo  A- 
Banham,  F.  E.  C.  V.  S.  New  edition.  Cioth,  size 
4  x  5  1-2,  192  pages 1  00 

BAUCHEB.  "Method  of  Horsemanship."  Including 
the  Breaking  and  Training  of  Horses.  Bv 
F.  Baucher 1  qq 

BELL.     (*)"The  Veterinarian's   Call   Book   (Perpetual)." 

By  Roscoe  R.  Bell,  D.V.S.,  editor  of  the  American 
Veterinary  Review.     Completely  revised. 

A  visiting  list,  that  can  be  commenced  at  anv  time 
and  used  until  full,  containing  much  useful  informa- 
tion for  the  student  and  the  busy  practitioner. 
Among  contents  are  items  concerning:  Prescription 
writing;  Veterinary  Drugs;  Poisons;  Solubility  of 
Drugs;  Composition  of  Milk,  Bile,  Blood,  Gastric 
Juice,  Urine,  Saliva;  Respiration;  Dentition;  Temp- 
erature, etc.,  etc.  Bound  in  flexible  leather,  with 
flap  and  pocket , , ?  1  25 


BITTING.    "Cadiot's  Exercises  in  Equine  Surgery." 

See  "Cadiot." 
BRADLEY.         "  Outlines      of     Veterinary    Anatomy." 

By  O.Charnock  Bradley,  Member  of  the  Royal  Col- 
lege of  Veterinary  Surgeons ;  Professor  of  Anatomy 
In  the  New  Veterinary  College,  Edinburgh. 

The  author  presents  the  most  important  facts  of 
veterinary  anatomy  in  as  condensed  a  form  as  possible, 
consistent  with  lucidity.     12mo. 

Complete  in  three  parts. 

Pabt  I.  :      The.  Limbs  (cloth) 1  25 

Part  II.  :     The  Trunk  (paper) 1  25 

Part  III. :    The  Head  and  Neck  (paper) 1  25 

The  Set  complete 3  25 

CADIOT.     "  Exercises  in  Equine  Surgery."     By  P.  J. 

Cadiot.  Translated  by  Prof.  A.  W.  Bitting,  D.V.M. 
Edited  by  Prof.  A.  Liautard,  M.D.V.M.  Size,  6  x  9X- 
cloth,  illustrated 2  50 

—  "Roaring   in    Horses."     Its    Pathology   and    Treatment. 

This  work  represents  the  latest  development  in  oper- 
ative methods  for  the  alleviation  of  rqaring.  Each 
step  is  most  clearly  defined  by  excellent  full-page 
illustrations.  By  P.  J.  Cadiot,  Professor  at  the 
Veterinary  School,  Alfort.  Translated  by  Thos.  J. 
Watt  Dollar,  M.R.C.V.S.,  etc.  Cloth,  size  51-4x7  1-8, 
77  pages,  illustrated 75 

—  "Studies  in  Clinical  Veterinary  Medicine  and  Surgery." 

By  P.  J.  Cadiot.  Translated,  edited,  and  supplemented 

with  49  new  articles  and  31  illustrations  by  Jno.  A.  W. 

Dollar,  M.R.C.V.S.     Cloth,  size  7x9  3-4,  619  pages, 

94  black  and  white  illustrations 5  25 

— (V  A  Treatise  on  Surgical  Therapeutics  of  the  Domestic 

Animals."  By  P.  J.  Cadiot  and  J.  Almy.     Translated 

by  Prof.  A.  Liautard  M.D..V.M. 

General  Surgery. — Means  of  restraint  of  animals, 
general  anaesthesia,  local  anrethesia,  surgical  anti- 
sepsis and  asepsis,  hematosis,  cauterization,  firing, 

Diseases  Common  to  all  Tissues.— Inflammation, 
abscess,  gangrene,  ulcers,  fistula,  foreign  bodies, 
traumatic  lesions,  complications  of  traumatic  les- 
ions, granulations,  cicatrices,  mycosis,  virulent 
diseases,  tumors. 

Diseases  Special  to  all  Tissues  and  Affections  of 
the  Extremities.— Diseases  of  skin  and  cellular  tis- 
sue, of  serous  bursae,  of  muscles,  of  tendons,  of 
tendinous  svnovial  sacs,  of  aponeurosis,  of  arteries, 
of  veins,  of  lymphatics,  of  nerves,  of  bones,  of 
articulations. 

Cloth,  size  6x9,  580  pages,  118  illustrations 4  50 

CAMPBELL  and  LE CROIX.  (•)«* Essentials  of  Para- 
sitology," with  a  brief  discourse  on  Zoology.  Size 
5  3-4  x  8  1-2,  96  pages,  with  three  Charts 1  OQ 


CHAPMAN.  "Manual  of  the  Pathological  Treatment 
of  Lameness  in  the  Horse,"  treated  solely  by 
mechanical  means.  By  George  T.  Chapman.  Cloth, 
size  6x9,  124  pages  with  portrait 2  00 

CLARKE.  "Chart  of  the  Feet  and  Teeth  of  Fossil 
Horses."  By  W.  H.  Clarke.  Card,  size  9  1-2  x  12. .   25 

—"Horses'  Teeth."  Fourth  edition,  re-revised,  with  second 
appendix.     Cloth,  size  5  1-4x7  1-2,  322  pp.,  illus .  .2  £0 

CLEAVELAND.        "  Pronouncing      Medical      Lexicon." 

Pocket  edition.  By  C  H.  Cleveland,  M.D.  Cloth 
size  3  1-4x4  1-2,  302  pages 75 

CLEMENT.  "Veterinary  Post  Mortem  Examina- 
tions." By  A.  W.  Clement,  V.S.  The  absence  in  the 
English  language  of  any  guide  in  making  autopsies 
upon  the  lower  animals,  induced  Dr.  Clement  to 
write  this  book,  trusting  that  it  would  prove  of  prac- 
tical value  to  the  profession.  Cloth,  size  5x7  1-2,  64 
pages,  illustrated 75 

CO UBTENA  T.  (f)  "Manual  of  the  Practice  of  Veterinary 
Medicine."  By  Edward  Courtenay,  V.  S.  Revised  by 
Frederick  T.  G.  Hobday,  F.R.C.V.S.  Second  edition. 
Cloth,  size  5  1-4x7  1-2,  573  pages    2  75 

COX.        "  Horses  :     In    Accident    and    Disease."       The 

sketches  introduced  embrace  various  attitudes  which 
have  been  observed,  such  as  in  choking;  the  disorders 
and  accidents  occurring  to  the  stomach  and  intestines ; 
affection  of  the  brain  ;  and  some  special  forms  of  lame- 
ness, etc.  By  J.  Roalfe  Cox,  F.R.C.V.S.  Cloth,  size 
6  x  9,  28  full  page  illustrations 1  50 

DALRTMPLE.  (*)" Veterinary  Obstetrics."  A  compen- 
dium for  th«  use  of  advanced  students  and  Practi- 
tioners. By  W.  H.  Dalrymple,  M.  R.  C.  V.  S., 
principal  of  the  Department  of  Veterinary  Science  in 
the  Louisiana  State  University  and  A.  &'M.  College; 
Veterinarian  to  the  Louisiana  State  Bureau  of 
Agriculture,  and  Agricultural  Experiment  Stations. 
Second  edition  revised.  Cloth,  she  6x9  1-4,162  pages, 
51  illustrations 2  50 

DALZIEL.  "Breaking  and  Training  Dogs."  Part  I,  by 
Pathfinder.  Part  II,  by  Hugh  Dalziel.  Cloth, 
illustrated 2  50 

—  "The    Collie."    By  Hugh  Dalziel.     Paper,  illustrated. .. .  50 

—  "The  Diseases  of  Dogs."    Causes,  symptoms  and  treatment. 

By  Hugh  Dalziel.  Illustrated.  Paper,  50c.  Cloth,  1  (0 

—  "Diseases  of  Horses."    Paper 50 

—  "  The  Fox  Terrier."    By  Hugh  Dalziel.    Paper,  50 ;  clo.l  00 

—  "The  Greyhound."   Cloth,  illus 1  OH) 

—  "  The  St.  Bernard,"    Cloth,  illustrated. . , , . .   ...,,,,.  l  00 


DANA.  "Tables  in  Comparative  Physiology."  By  Prof. 
C.  L.  Dana,  M.D.     Chart,  17  x  17 36 

DANCE.  "  Veterinary  Tablet."  By  A.  A.  Dance.  Chart, 
17  x  24,  mounted  on  linen,  foldf ri  in  a  cloth  case  for 
the  pocket,  size  3  3-4  x  G  1-2.  Shews  at  a  glance  the 
synopsis  of  the  diseases  of  horses,  cattle  and  dogs ; 
with  their  cause,  symptoms  and  cure 75 

DE  BRUIN.  (*)" Bovine  Obstetrics."  ByM.  G.  De Bruin 
Instructor  of  Obstetrics  at  the  State  Veterinary 
School  in  Utrecht.  Translated  by  W.  E.  A.  Wyman, 
formerly  Professor  of  Veterinary  Science  at  Clemson 
A.  it  M.  College,  and  Veterinarian  to  the  South 
Carolina  Experiment  Station.      Cloth,  size  6x9,  382 

pages,  77  illustrations 5  00 

Synopsis  of  the  Essential  Features  of  tbe  Work 

1.  Authorized  translation. 

2.  The  only  obstetrical  work  which  is  up  to  date. 

3.  Written  by  Europe's  leading  authority  on  the  subject. 

4.  Written  by  a  man  who  has  practiced  the  art  a  lifetime. 

5.  Written  by  a  man  who,  on  account  of  his  eminence  as 
bovine  practitioner  and  teacher  of  obstetrics,  was  selected 
by  Prof.  Dr.  Frohner  and  Prof.  Dr.  Bayer  (Berlin  and 
Vienna),  to  discuss  bovine  obstetrics  both  practically  and 
scientifically. 

6.  The  only  work  containing  a  thorough  differential  diag- 
nosis of  ante  and  post  partum  diseases. 

7.  The  only  work  doing  justice  to  modern  obstetrical 
surgery  and  therapeutics. 

8.  Written  by  a  man  whose  practical  suggestions  revolu- 
tionized the  teaching  of  veterinary  obstetrics  even  in  the 
great  schools  of  Europe. 

9.  The  only  work  dealing  fully  with  the  now  no  longer 
obscure  contagious  and  infectious  diseases  of  calves. 

10.  Absolutely  original  and  no  compilation.     * 

11.  The  only  work  dealing  fully  with  the  difficult  problem 
of  teaching  obstetrics  in  the  colleges. 

12.  The  only  work  where  the  practical  part  is  not  over- 
shadowed by  theory. 

...  A  veterinarian,  particularly  if  his  location  brings  him  in 
contact  with  obstetrical  practice,  who  makes  any  pretence  toward 
being  scientific  and  in  possession  of  modern  knowledge  upon  this 
subject,  will  not  be  without  this  excellent  work,  as  it  is  really  a  very 
valuable  treatise.—  Prof.  Boscoc  B.  Bell,  in  the  American  Veterinary 
Beview. 

In  translating  into  English  Professor  De  Bruin's  excellent  text- 
book on  Bovine  Obstetrics,  Dr.  Wyman  has  laid  British  and  American 
veterinary  surgeons  and  students  under  a  debt  of  gratitude.  The 
works  represents  the  happy  medium  between  the  booklets  which  are 
adapted  for  cramming  purposes  by  the  student,  and  the  ponderous 
tomes  which,  although  useful  to  the  teacher,  are  not  exactly  suited  to 
the  requirements  of  the  everyday  practitioner  .  .  .  We  can  strongly 
recommend  the  work  to  veterinary  students  and  practitioners.— The 
Journal  of  Comparative  Pathology  and  Therapeutics. 

DOLLAR.  f*)" Diseases  of  Cattle,  Sheep,  Goats  and 
Swine."  Bv  G.  Moussu  and  Jno.  A.  W.  Dollar, 
M.R.C.  V.S.  Size  6x9  1-2,  785  pages,  329  illustrations 
in  the  text  and  4  full  page  plates 8  75 

—  (t)"A  Hand-book  of  Horse-Shoeing,"  with  Introductory 
chapters  on  the  anatomy  and  physiology  of  the 
horse's  foot.  By  Jno.  A.  W.  Dollar,  M.R.C. V.S., 
with  the  collaboration  of  Albert  Wheatley,  F. B.C. V.S. 
Cloth,  size  6x8  1-2,  433  pages,  406  illustrations  .  .4  75 


DOLLAR  (continued) 

—  (f) "Operative  Technique."     Volume  1  of  "The  Practice  of 

Veterinary  Surgery."  Cloth,  size  6  3-4  x  10,  264  pages, 
272  illustrations 3  75 

—  "  General  Surgery."    Volume  2  of  "The  Practice  of  Veter- 

inary Surgery."     In  preparation. 

—  (f)"  Regional   Veterinary  Surgery."     Volume  3   of  "The 

Practice  of  Veterinary  Surgery."  By  Drs.  Jno.  A. 
W.  Dollar  and  H.  Moller.  Cloth,  size  6  1-2  x  10  853 
and  xvi  pages,  315  illustrations 6  25 

—  "Cadiot's  Clinical  Aeterinary  Medicine  and  Surgery." 

See  "  Cadiot." 

—  "Cadiot's  Roaring  in  Horses."    See  "  Cadiot." 

DUN.     "Veterinary  Medicines,  their  Actions  and  Uses." 

By  Finlay  Dun,  V.S.,  late  lecturer  on  Materia 
Medica  and  Dietetics  at  the  Edinburgh  Veterinary 
College,  and  Examiner  in  Chemistry  to  the  Boyal 
College  of  Veterinary  Surgeons.  Edited  by  James 
Macqueen,  F.E.C.V.S.  Tenth  revised  English  edition. 
Cloth,  size  6x9 3  75 

FLEMING.  "  The  Contagious  Diseases  of  Animals."  Their 
influence  on  the  wealth  and  health  of  nations  and  how 
they  are  to  be  combated.  Paper,  size  5x7  1-2, 
30  pages 25 

—  "Human  and  Animal  Variolse."    A  Study  in  Comparative 

Pathology.      Paper,  size  5  1-2x8  1-2,  61  pages 25 

—  "Parasites  and  Parasitic  Diseases  of  the  Domesticated 

Animals."  By  L.  G.  Neumann.  Translated  by 
Dr.  Fleming.     See  "  Neumann." 

—  "Operative  Veterinary  Surgery."     Vol.    I,    by  Dr.  Geo. 

Fleming,  M.R.O.V.S.  This  valuable  work,  one  of  the 
most  practical  treatises  yet  issued  on  the  subject  in 
the  English  language, is  devoted  to  the  common  opera- 
tions of  Veterinary  Surgery ;  and  the  concise  descrip- 
tions and  directions  of  the  text  are  illustrated  with 
numerous  wood  engravings.     Cloth,  size  6x9  1-4,  285 

and  xviii  pages,  343  illustrations .2  75 

(*)Vol.  II,  edited  and  passed  through  the  press  by 
W.  Owen  Williams,  F.R.C.V.S.  Cloth,  size  6x9  1-4. 
430  and  xxxvii  pages,  344  illustrations 3  25 

—  "  Roaring     in     Horses."  By    Dr.     George      Fleming, 

F.R.C.V.S.  Its  history,  nature,  causes,  prevention 
and  treatment.  Cloth,  size  5  1-2x8  3-4,  160  pages,  21 
engravings,  1  colored  plate 1  5u 

—  "  Veterinary  Obstetrics."    Including  the  Accidents  and  Dis- 

eases incidentto  Pregnancy,  Parturition,  and  the  Early 
Age  in  Domesticated  Animals.  By  Geo.  Fleming 
F.R.C.V.S.    Cloth,  size  6x8  3-4,  758  pages,  illus.6  25 


GOTTHIEL.     (•)"!    Manual    of    General     Histology." 

By  Wm.  S.  Gottheil,  M.D.,  Professor  of  Pathology  in 
the  American  Veterinary  College,  New  York;  etc.,  etc. 
Histology  is  the  basis  of  the  physician's  art,  as 
Anatomy  is  the  foundation  of  the  surgeon's  science. 
Only  by  knowing  the  processes  of  life  can  we  under- 
stand the  changes  of  disease  and  the  action  of 
remedies ;  as  the  architect  must  know  his  building 
materials,  so  must  the  practitioner  of  medicine  know 
the  intimate  structure  of  the  body.  To  present  this 
knowledge  in  an  accessible  and  simple  form  has 
been  the  author's  task.  Second  edition  revised. 
Cloth,  size  5  1-2  x  8,  152  pages,  68  illustrations. .  .1  00 

GRESSWELL.    "Diseases  and  Disorders  of  the  Horse." 

A  Treatise  on  Equine  Medicine  and  Surgery,  being  a 
contribution  to  the  science  of  comparative  pathology. 
By  Albert,  Jas.  B.  and  Geo.  Gresswell.  Cloth,  size 
5  3-4x8  3  4,  227  pages,  illustrated 1  75 

—  "  The  Bovine  Prescriber."    For  the  use  of  Veterinarians 

and  Veterinary  Students.  Second  edition,  revised 
and  enlarged,  bv  James  B.  and  Albert  Gresswell, 
M.R.C.V.S.     Cloth,  size,  5  x  7  1-2,  102  pages 75 

—  "The  Equine  Hospital  Prescriber."    For  the  use  of  Veter- 

inary Practitioners  and  Students.  Third  edition  re- 
vised and  enlarged,  by  Drs.  James  B.  and  Albert 
Gresswell,  M.R.C.V.S.  Cloth,  size  5x7  1-2,  165 
pages 75 

—  Manual  of  "The  Theory  and  Practice  of  Equine  Medicine." 

By  James  B.  Gresswell,  F.R.C.V.S.,  and  Albert 
Gresswell,  M.R.C.V.S.  Second  edition  revised. 
Cloth,  size  5  1-4  x7  1-2,  539  pages 2  75 

—  (f)  "Veterinary  Pharmacopeia  and  Manual  of  Comparative 

Therapy."  By  George  and  Charles  Gresswell,  with 
descriptions  and  physiological  actions  of  medicines, 
by  Albert  Gresswell.  Second  edition  revised  and 
enlarged.     Cloth,  6x8  3-4,  457  pages 3  60 

HASSLOCH.  "  A  Compend  of  Veterinary  Materia  Medica 
and  Therapeutics."  By  A.  C.  Hassloch,  V.S., 
Lecturer  on  Materia  Medica  and  Therapeutics,  and 
Professor  of  Veterinary  Dentistry  at  the  New  York 
College  of  Veterinarv  Surgeons  and  School  of  Compa- 
rative Medicine,  N.  Y.  Cloth,  size  5  1-4x7  1-2,  225 
pages 1  50 

HEATLEY.  "  The  Stock  Ovtner's  Guide."  A  handy  Medi- 
cal Treatise  for  every  man  who  owns  an  ox  or  cow. 
Bv  George  S.  Heatley,  M.R.C.V.S.  Cloth,  size 
5  1-4  x  8,  172  pages 1  26 


HILL.  (t)"The  Diseases  of  the  Cat."  By  J.  Woodroffc 
Hill,  F.R.C.V.S.     Cloth,  size  5  1-4x7  1-2,  123  pages, 

illustrated 1  25 

Written  from  the  experience  of  many  years'  prac- 
tice and  close  pathological  research  into  the  maladies 
to  which  our  domesticated  feline  friends  are  liable — a 
subject  which  it  must  be  admitted  has  not  found  the 
prominence  iu  veterinary  literature  to  which  it  is 
undoubtedly  entitled. 

—  "The   Management   and   Diseases    of  the   Dog."     By  J. 

Woodroffe  Hill,  F.R.C.V.S.  Cloth,  size  5x7  1-2, 
extra  fully  illustrated. 

HINEBAUCH.    "Veterinary  Dental  Surgery."    By  T.  D. 

Hinebauch,  M.S.V.S.  For  the  use  of  Students,  Prac 
titioners  and  Stockmen.  Cloth,  size  5  1-4  x  8,  256 
pages,  illustrated 2  Ou 

HO  ARE.  (*)"A  Manual  of  Veterinary  Therapeutics  and 
Pharmacology."  By  E.  Wallis  Hoare,  F.R.C.V.S. 
Cloth,  size  5  1-4x7  1-4,  xxvi  plus  78t)  pages 4  75 

HOBDAY,  (f)"  The  Castration  of  Cryptorchid  Horses  and 
the  Ovariotomy  of  Troublesome  Mares."  By 
Frederick  T.  G.  Hobday,  F.R.C.V.S.  Cloth,  size 
5  3-4  x  8  3  -4,  11 6  pages,  34  illustrations 1  75 

HUNTING,  (f)  The  Art  of  Horse-shoeing.  A  manual 
for  Horseshoers.  By  William  Hunting,  F.R.C.V.S., 
ex-President  of  the  Royal  College  of  Veterinary  Sur- 
geons. One  of  the  most  up-to-date,  concise  books  of 
its  kind  in  the  English  language.  Cloth,  size  6x9  1-4. 
126  pages,  96  illustrations 1  00 

JENKINS.  (*)"  Anatomical  and  Physiological  Model  of 
the  Cow."  Half  life  size.  Composed  of  superposed 
plates,  colored  to  nature,  showing  internal  organs, 
muscles,  skeleton,  etc.,  mounted  on  strong  boards, 
with  explanatory  text.  Size  of  Model  opened 
10  ft.  x  3  ft.,  closed  3  ft.  x  1^  ft 12  00 

—  "Anatomical  and  Physiological   Model    of  the   Horse." 

Half  life  size.     Size  of  Model  38  x  41  in 12  00 

Models  also  in  smaller  sizes  of  the  Horse,  Cow, 
Dog,  Sheep  and  Pig,  at  $3.50  each. 

JONES       (V'The   Surgical    Anatomy    of   the    Horse." 

By  Jno.  T.  Share  Jones,  M.R.C.V.S.  Parts  I,  II  and 
III  ready.  To  be  completed  in  four  paits.  Each 
part — paper,  $±.25  ;  cloth,  $5.00. 


ROBERT.     "Practical    Toxicology   for  Physicians    and 

Students  "  By  Professor  Dr.  Rudolph  Robert, 
Medical  Director  of  Dr.  Brehmer's  Sanitarium  for 
Pulmonary  Diseases  at  Goerbersdorf  in  Silesia  (Prus- 
sia), late  Director  of  the  Pharmacological  Institute, 
Dorpat,  Russia.  Translated  and  edited  by  L.  H. 
Friedburg,  Ph.D.  Authorized  Edition.  Practical 
knowledge  by  means  of  tables  which  occupy  little 
space,  but  show  at  a  glance  similarities  and  differ- 
ences between  poisons  of  the  same  group.  Also  rules 
for  the  Spelling  and  Pronunciation  of  Chemical  Terms, 
a^  adopted  by  the  American  Association  for  the  Ad- 
vancement of  Science.    Cloth,  6  1-2  x  10,  201  pp.. 2  60 

ROCH.  "Etiology  of  Tuberculosis."  By  Dr.  R.  Koch. 
Translated  by  T.  Saure.  Cioth,  size  6x9  1-4,  97 
pages 1  00 


LAW.  " Farmers'  Veterinary  Adviser."  A  Guide  to  the 
Prevention  and  Treatment  of  Disease  in  Domestic 
Animals.  By  Prof.  James  Law.  Cloth,  size 
5  1-4x7  1-2,  illustrated 3  00 


LIAUTARD.  (f)." Animal  Castration."  A  concise  and 
practical  Treatise  on  the  Castration  of  the  Domestic 
Animals.  The  only  work  on  the  subject  in  the 
English  language.  By  Alexander  Liautard,  M.D..V.S. 
Having  a  fine  portrait  of  the  author.  Tenth  edition 
revised  and  enlarged.  Cloth,  size  6  1-4x7  1-2,  165 
pages,  45  illustrations 2  00 

.  .  .  The  most  complete  and  comprehensive  work  on  the 
sub.iect  in  English  veterinary  literature.— American  Agri- 
culturist. 

—  "Cadiot's  Exercises  in  Equine  Surgery,"     Translated  by 

Prof.  Bitting  and  edited  by  Dr.  'Liautard. 
See  "  Cadiot." 

—  "A  Treatise  on  Surgical  Therapeutics  of  the  Domestic 

Animals."  By  Prof.  Dr.  P.  J.  Cadiot  and  J.  Almy. 
Translated  by  Prof.  Liautard.     See  "  Cadiot." 

—  "  How  to  Tell   the   Age   of  the  Domestic  Animal."    By 

Dr.  A.  Liautard,  M.D.,  V.S.  Standard  work  upon 
this  subject,  concise,  helpful  and  containing  many 
illustrations.  Cloth,  size  5x7  1-2,  35  pages,  42 
illustrations 60 

—  "Lameness  of  Horses  and  Diseases  of  the    Locomotory 

Apparatus."  By  A.  Liautard,  M.D., V.S-  This  work 
is  the  result  of  Dr.  Liautard's  many  years  of  experi- 
ence.   Cloth,  size  5  1-4x7  1-2,  314  pages 2  60 


LIAUTARD  (continued). 

—  (*)"  Manual  of  Operative  Yeterinary  Surgery  "  By  A. 
Liautard,  M.D.,  V.M.  Engaged  for  years  in  the  work 
of  teaching  this  special  department  of  veterinary 
medicine,  and  having  abundant  opportunities  of 
realizing  the  difficulties  which  the  student  who 
earnestly  strives  to  perfect  himself  in  his  calling  is 
obliged  to  encounter,  the  author  formed  the  deter- 
mination to  facilitate  his  acquisition  of  knowledge, 
and  began  the  accumulation  of  material  by  the  com- 
pilation of  data  and  arrangement  of  memorandum, 
with  the  recorded  notes  of  his  own  experience,  the 
fruit  of  a  long  and  extended  practice  and  a  careful 
study  of  the  various  authorities  who  have  illustrated 
and  organized  veterinary  literature.  Revised  edition, 
with  complete  index.  Cloth,  size  6  1-4  x  9,  xxx  and  803 
563  illustrations 5  00 


—  "Pellerin's    Median    Neurotomy    in    the   Treatment   of 

Chronic  Tendinitis  and  Periostosis  of  the  Fetlock." 

Translated  by  Dr.  A.  Liautard.     See  "  PzUerin." 

—  "Vade  Mecum   of  Equine   Anatomy/'     By  A.  Liautard, 

M.D.V.S.  For  the  use  of  advanced  students  and 
veterinary  surgeons.  Third  edition.  Cloth,  size 
5x7  1-2,  30  pages  and  10  full  page  illustrations  of 
the  arteries . 2  00 

—  Zundel's  "  The  Horse's  Foot  and  Its  Diseases." 

See  "  Zundel." 

LONG.  "Book  of  the  Pig."  Its  selection,  Breeding, 
Feeding  andManagement.    Cloth 4.00 

LOWE.  (f)"  Breeding  Eacehorses  by  the  Figure 
System."  Compiled  by  the  late  C.  Bruce  Lowe. 
Edited  by  William  Allison,  "  The  Special  Commis- 
sioner," London  Sportsman,  Hon.  Secretary  Sporting 
League,  and  Manager  of  the  International  Horse 
Agency  and  Exchange.  With  numerous  fine  illustra- 
tions of  celebrated  horses.  Cloth,  size  8  x  10,  262 
pages • 7  50 

LUDLOW.  "Science  in  the  Stable";  or  How  a  Horse 
can  be  Kept  in  Perfect  Health  and  be  Used  Without 
Shoes,  in  Harness  or  under  the  Saddle.  With  the 
Reason  Why.  Second  Edition.  By  Jacob  R.  Ludlow, 
M.D.  Late  Staff  Surgeon,  U.  S.  Army.  Paper,  size 
4  1-2x5  3-4,  166  pages 50 

LUPTON.  "Horses:  Sound  and  Unsound,"  with 
Law  relating  to  Sales  and  Warranty.  By  J.  lrvino 
Lupton.  F.R.C.V.S.  Cloth,  size  6  3-4  x  7  1-2,  217 
pages,  23  illustrations 1  25 


M'FADYEAN.  (f)  "  Anatomy  of  the  Horse."  Second 
edition  completely  revised.  A  Dissection  Guide. 
By  John  M'Fadyean,   M.B.,  B.Sc,  F.R.S.E.      Cloth. 

size  6  x  83  4,  388  pages,  illustrated 8  50 

This  book  is  intended  for  Veterinary  students,  and 
offers  to  them  in  its  48  full-page  colored  plates, 
54  illustrations  and  excellent  text,  a  valuable  and 
practical  aid  in  the  study  of  Veterinary  Anatomy, 
especially  in  the  dissecting  room. 

—  **  Comparative  Anatomy  of  the   Domesticated  Animals." 
By  J.  M'Fadyean.     Profusely  illustrated,  and  to  be 
issued  in  two  parts. 
Part  I— Osteology,   ready.      Size  5  1-2x8  1-2,   166 

pages,  132  illustrations.     Paper,  2  50;  cloth 2  76 

(Part  II  in  preparation.) 

MAGNER.  "Standard  Horse  and  Stock  Book."  By 
D.  Magner.  Comprising  over  1,000  pages,  illustrated 
with  1756  engravings.     Leather  binding 6  00 

MILLS.  "How  to  Keep  a  Dog  in  the  City."  By 
Wesley  Mills,  M.D.,  D.V.S.  It  tells  how  to  choose, 
manage,  house,  feed,  educate  the  pup,  how  to  keep  him 
clean  and  teach  him  cleanliness.  Paper,  size  5x7 1-2, 
40  pages 26 

MOHLER.  "Handbook  of  Meat  Inspection."  By  Robert 
Ostertag,  M.D.  Translated  by  Earley  Vernon 
Wilcox,  A.M.,  Ph.D.  With  an  introduction  by 
John  R.  Mohler,  V.M.D.,  A.M.     See  "  Ostertag." 

MOLLER  —  DOLLAR.  (f)  "Regional  Veterinary 
Surgery."    See  "Dollar." 

MOSSELMAN-L1ENAUX.  "Manual  of  Veterinary 
Microbiology."  By  Professors  Mosselman  and 
Lienaux,  Nat.  Veterinary  College,  Cureghem,  Belgium. 
Translated  and  edited  by  R.  R.  Dinwiddie,  Professor 
of  Veterinary  Science, College  of  Agriculture,  Arkansas 
State  University.  Cloth,  size  5  1  2  x  8,  342  pages, 
illustrated 2  00 

MOUSSV.  O"  Diseases  of  Cattle,  Sheep,  Goats  and 
Swine."     See  "  Dollar." 

NEUMANN.  (*)"A  Treatise  on  Parasites  and  Parasitic 
Diseases  of  the  Domesticated  Animals."  A  work 
to  which  the  students  of  human  or  veterinary  medi- 
cine, the  sanitarian,  agriculturist  or  breeder  or  rearer 
of  animals,  may  refer  for  full  information  regarding 
the  external  and  internal  Parasites— vegetable  and 
animal — which  attack  various  species  of  Domestic 
Animals.  A  Treatise  by  L.  G.  Neumann,  Professor 
at  the  National  Veterinary  School  of  Toulouse. 
Translated  and  edited  by  Geo.  Fleming,  C.B.,  L.L.D.. 
F.R  O.V.S.  Second  edition,  revised  and  edited  by 
James  Macqueen,  F.R.C.V.S.,  Professor  at  the  Royal 
Veterinary  College,  London.  Cloth,  size  6  3-4  x  in, 
xvi  +  698  pages,  365  illustrations 6  76 


tfO CARD.    "The  Animal  Tuberculoses,  and  their  Relation 

to  Human  Tuberculosis."  By  Ed.  Nocard,  Prof,  of  the 
Alfort  Veterioary  College.  Translated  by  H.  Scurfield, 
M.D.  Ed.,  Ph.  Camb.  Cloth,  5  x  7  1-2, 143  pages ..  1  00 
Perhaps  the  chief  interest  to  doctors  of  human 
medicine  in  Professor  Nocard's  book  lies  in  the 
demonstration  of  the  small  part  played  by  heredity, 
and  the  great  part  played  by  contagion  in  the  propa- 
gation of  bovine  tuberculosis. 

JVUNtf.  (•)««  Veterinary  Toxicology."  By  Joshua  A.  Nunn, 
F.R.C.V.S.  The  study  of  toxicology  is  intimately 
blended  with  other  biological  sciences,  particularly 
physiology  and  chemistry,  both  of  which  it  on  many 
occasions  overlaps.  A  carefully  arranged  and  com- 
plete index  is  given  in  the  front  of  the  volume. 
Cloth,  size  Gx  8  3-4,  vii  +  191  pages 1  75 

OSTEBTAG.    (*)  "  Handbook  of  Meat  Inspection."      By 

Robert  Ostertagr,  M.D.  Authorized  Translation  by 
Earley  Vernon  Wilcox.  A.M.,  Ph.D.  With  an  intro- 
duction by  John  R.  Mohler,  V.M.D.,  A.M.  The  work 
is  exhaustive  and  authorative  and  has  at  once  become 
the  standard  authority  upon  the  subject  Second 
edition,  revised.  Cloth,  size  6  3-4x9  3-4,  920  pages, 
260  illustrations  and  1  colored  plate 7  50 

PAL  LIN.    (*)  «  A  Treatise  on  Epizootic  Lymphangitis."  By 

Capt.  W.  A.  Pallin,  F.R.C.V.S.  In  this  work  the 
author  has  endeavored  to  combine  his  own  experience 
with  that  of  other  writers  and  so  attempts  to  give  a 
clear  and  complete  account  of  a  subject  about  which 
there  is  little  at  present  in  English  veterinary  liteA- 
ture.  Cloth,  size  5  3-4x8  1-2,  90  pages,  with  17  fine 
full  page  illustrations 1  25 

PEGLEJR.    "  Goat  Keeping  for  Amateurs."     Paper,  5x7i, 
77  pages,  illustrated gy 

PELEERIN.      "Median   Neurotomy    in    the  Treatment 
of  Chronic  Tendinitis  and  Periostosis  of  the  Fetlock." 

By  O.  Pellenn,  late  repetitor  of  Clinic  and  Surgery  to 
the  Alfort  Veterinary  School.  Translated,  with  Addi- 
tional Facts  Relating  to  It,  by  Prof.  A.  Liautard,  M.D  , 
V.M.  Having  rendered  good  results  when  performed 
by  himself,  the  author  believes  the  operation,  which 
consists  in  dividing  the  cubito-plantar  nerve  and  in 
excising  a  portion  of  the  peripherical  end,  the  means 
of  improving  the  conditions,  and  consequently  the 
values  of  many  apparently  doomed  animals.  Agricul- 
ture in  particular  will  be  benefited. 

The  work  is  divided  into  two  parts.  The  first  covers 
the  study  of  Median  Neurotomy  itself ;  the  second 
the  exact  relations  of  the  facts  as  observed  by  the 
author.     Boards,  6x9  1-2,  61  pages,  illustrated     1  00 


PETERS.  "  A  Tuberculous  Herd— Test  with  Tuber- 
culin." By  Austin  Peters,  M.  R.  C.  V.  S.,  Chief 
Inspector  of  Cattle  for  the  New  York  State  Board  of 
Health  during  the  winter  of  1892-93.     Pamphlet. . .  .25 

REYNOLDS.  "An  Essaj  on  the  Breeding  and  Manage- 
ment of  Draught  Horses."  By  R.  S.  Reynolds, 
M.R.C.  V.S.     Cloth,  size  5  1-2x8  3-4,  104  pages.  .1  40 

ROBERGE.  "  The  Foot  of  the  Horse,"  or  Lameness 
and  all  Diseases  of  the  Feet  traced  to  an  Unbalanced 
Foot  Bone,  prevented  or  cured  by  balancing  the  foot. 
By  David  Roberge.  Cloth,  size  6x9  1-4,  308  pages, 
illustrated 5  00 

SESSIONS.  (*)"  Cattle  Tuberculosis,"  a  Practical  Guide  to 
the  Agriculturist  and  Inspector.  By  Harold  Sessions, 
F.R,C.  V.S.,  etc.     Second  edition.     Size  5x7  1-4,  vi  -+- 

120  pages 1  00 

The  subject  can  be  understood  by  those  who  have 
to  deal  purticularly  with  it,  yet  who,  perhaps,  have 
not  had  the  necessary  training  to  appreciate  technical 
phraseology. 

SEW  ELL,.  "The  Examination  of  Horses  as  to  Sound- 
ness and  Selection  as  to  Purchase."  By  Edward 
Sewell,  M.R.C. V.S.  Paper,  size  51-2x8  1-2,  86  pages, 
illustrated  with  8  plates  in  color 1  60 

It  is  a  great  advantage  to  the  business  man  to 

know  something  of  the  elements  of  law.  and  nobody 
ought  either  to  buy  or  own  a  horse  who  does  not  know 
something  about  the  animal.  That  something  this  book 
gives,  and  gives  in  a  thoroughly  excellent  way 

SMITH.  (•)'«  A  Manual  of  Veterinary  Physiology."  By 
Vet.  Capt.  F.  Smith,  C.M.S.,  M.R.C.V.S.,  Examiner  in 
Physiology,  Royal  College  of  Veterinary  Surgeons, 
author  of  "A  Manual  of  Veterinary  Hygiene."  A 
completely  revised  and  enlarged  edition  just  pub- 
lished.    Cloth,  6x8  3-4,  720  pp,  102  illust'ns 4  25 

The  whole  book  has  been  carefully  revised  and 
brought  up  to  date.  All  the  important  advances  of  the 
last  few  years  have  been  embodied.  The  chapter  on 
the  nervous  system  has  been  specially  revised  by  Prof,. 
Sherrington,  whose  remarkable  work  on  the  "spinal 
dog"  has  been  introduced.  A  special  point  is  made 
of  the  bearing  of  physiology  on  pathology,  and  the 
utilization  of  physiology  to  the  better  understanding  of 
every-day  practice.  The  book  is  written  by  a  veterin- 
ary surgeon  for  veterinary  practitioners  and  students, 
and  is  the  only  work  in  the  English  language  which 
can  claim  to  be  purely  veterinary. 

—  (*)"  Manual  of  Veterinary  Hygiene."  Third  edition  revised. 
Cloth,  size  5  1-4x7  1-2,  xx  +  1036  pages,  with  255 

illustrations 4  75 

Recognizing  the  rapid  advance  and  extended  field 
of  the  subject  since  the  previous  issue,  the  author 
has  entirely  re-written  the  work  and  enlarged  its 
scope,  whieh  is  brought  thoroughly  up  to  date.  Con- 
tains over  600  more  pages  than  the  second  edition. 


STRANGEWAY.  (')" Veterinary  Anatomy."  Edited  by 
I.  Vaughaii,  F.L.S.,  M.R.O.V.S.  New  12th  American 
edition  revised.  Cloth,  size  6  1-4x9  1-2,  625  pages, 
224  illus 5  Ou 

SUSSDORF.    " Six  Large  Colored  Wall  Diagrams."    By 

Prof.  Sussdorf,  M.D.  (of  Gottingen).  Text  translated 
by  Prof.  W.  Owen  Williams,  of  the  New  Veterinary 
College,  Edinburgh.     Size,  44  inches  by  30  inches. 

1.— Horse.  4.— Ox. 

2. -Mare.  5.— Boar  and  Sow. 

3.— Cow.                        6.— Dog  and  Bitch. 
The  above  are  printed  in  eight  or  nine  colors. 
Showing  the    position   of   the    viscera  in  the  large 
cavities  of  the  body. 
Price,  unmounted , 1  75  each 

"      mounted  on  linen,  with  roller 3  50    " 

VAN  MATER.      «•  A    Text   Book    of    Teterinary  Oph- 

thalmology."  By  George  G.  Van  Mater,  M.D., 
D.V.S.,  Professor  of  Ophthalmology  in  the  American 
Veterinary  College ;  Oculist  and  Aurist  to  St.  Martha's 
Sanitarium  and  Dispensary;  Consulting  Eye  and  Ear 
Surgeon  to  the  Twenty-sixth  Ward  Dispensary ;  Eye 
and  Ear  Surgeon,  Brooklyn  Eastern  District  Dispen- 
sary, etc.  Illustrated  by  one  chromo  lithograph  plate 
and  71  engravings.  Cloth,  6x9  1-4,  151  pages.. .3  00 
.  .  .  We  intend  to  adopt  this  valuable  work  as  a  text 
book.— E.  J.  Creely,  D.V.S.,  Dean  of  the  San  Francisco 
Veterinary  College. 

VETERINARY      DIAGRAMS      in     Tabular      Form. 

Size,  28£  in.  x  22  inches.    Price  per  set  of  five 4  00 

Mounted  and  folded  in  case 7  60 

Mounted  on  roller  and  varnished 10  00 

No.  1.  "The  External  Form  and  Elementary  Ana- 
tomy of  the  Horse."  Eight  colored  illustrations — 
1.  External  regions  ;  2.  Skeleton  ;  3.  Muscles  (Superior 
Layer) ;  4.  Muscles  (Deep  Layer) ;  5.  Respiratory  Ap- 
paratus ;  6.  Digestive  Apparatus ;  7.  Circulatory  Ap- 
paratus ;  8.  Nerve  Apparatus ;  with  description. . .  .1  25 
Mounted  on  roller  and  varnished 2  25 

No.  2.  "The  Age  of  Domestic  Animals."  Forty-two 
figures  illustrating  the  structure  of  the  teeth,  indicat- 
ing the  Age  of  the  Horse,  Ox,  Sheep,  and  Dog,  with 

full  description 75 

Mounted  on  roller  and  varnished 2  00 

No.  3.    "  The  Unsoundness  and  Defects  of  the  Horse." 

Fifty  figures  illustrating — 1.  The  Defects  of  Confor- 
mation ;  2.  Defects  of  Position  ;  3.  Infirmities  or  Signs 
of  Disease ;  4.  Unsoundnesses ;  5.  Defects  of  the  Foot ; 

with  full  description 75 

Mounted  on  roller  and  varnished 2  00 


VETERINARY  DIAGRAMS  (continued). 

No.  4.  "The  Shoeing  of  the  Horse,  Mule  and  Ox." 
Fifty  figures  descriptive  of  the  Anatomy  and  Physio- 
logy of  the  Foot  and  of  Horse-shoeing 75 

Mounted  on  roller  and  varnished 2  00 

No.  5.  "The  Elementary  Anatomy,  Points,  and  But- 
cher's Joints  of  the  Ox."  Ten  colored  illustrations 
—  1.  Skeleton ;  2.  Nervous  System:  3.  Digestive 
System  (Right  Side);  4.  Respiratory  System  ;  5.  Points 
of  a  Fat  Ox  ;  6.  Muscular  System  ;  7.  Vascular  System; 
8.  Digestive  System  (Left  Side);  9.  Butcher's  Sections 
of  a  Calf ;   10.  Butcher's  Sections  of  an  Ox ;  with  full 

description 1  25 

Mounted  on  roller  and  varnished 2  25 

WALLET.    "  A  Practical  Guide  to  Meat  Inspection."    By 

Thomas  Walley,  M.R.C.V.S.,  late  principal  of  the 
Edinburgh  Royal  (Dick)  Veterinary  College;  Pro- 
fessor of  Veterinary  Medicine  and  Surgery,  etc. 
Fourth  Edition,  thoroughly  revised  and  enlarged 
hy  Stewart  Stockman,  M.R.C.V.S.,  Professor  of 
Pathology,  Lecturer  on  Hygiene  and  Meat  Inspection 
at  Dick  Veterinary  College,  Edinburgh.  Cloth,  size 
5  1-2  x  8  1-4,  with  45  colored  illus.,  295  pages 3  00 

WILCOX.  (*)"  Handbook  of  Meat  Inspection."  By  Robert 
Ostertag,  M.D.     See  "  Ostertag." 

WILLIAMS.  "Principles  and  Practice  of  Veterinary 
Medicine."  Author's  edition,  entirely  revised  and 
illustrated  with  numerous  plain  and  colored  plates. 
Bv  W.  Williams,  M.R.C.V.S.  Cloth,  size  5  3-4x8  3-4, 
868  pages 7  50 

—  "  Principles    and    Practice    of     Veterinary     Surgery." 

Author's  edition,  entirely  revised  and  illustrated 
with  numerous  plain  and  colored  plates.  By  W. 
Williams,  M.R.C.V.S.  Cloth,  size  6  1-2x9  1-4,  756 
pages 7  50 

WINSLO  W.  H "Veterinary  Materia  Medica  and  Therapeu- 
tics." By  Kenelm  Winslow.  B.A.S.,  M.D.V.,  M.D., 
(Harv.) ;  formerly  Assistant  Professor  of  Therapeutics 
In  the  Veterinary  School  of  Harvard  University; 
Fellow  of  the  Massachusetts  Medical  Society ;  Surgeon 
to  the  Newton  Hospital,  etc. 

Sixth  Edition,  Revised  in  1908 
The  most  completes  progressive  ami  scientific  book  on 
the  subject  in  the  English  language.     The  recojenized 
authority  on  Veterinary  Materia  Medica  ami  the  Stan- 
dard text-book  on  the  subject  in  veterinary  college*. 

Cloth,  size  6  1-4x9  1-4,  xii  +  859  pages 6  00 


WINS  LOW  (continued). 


(*) 


The  Production  and  Handling  of  Clean  Milk."    A 

complete,  plain,  practical  and  authoritative  guide  to 
the  production  and  distribution  of  clean  milk  for 
farmers,  health  officers,  milk  inspectors,  students  of 
agriculture  and  dairying,  country  gentlemen,  physi- 
cians and  others  interested  in  matters  pertaining  to 
dairying  and  hygiene.  The  book  also  contains  a 
general  outline  of  a  scheme  for  the  control,  supervi- 
sion and  inspection  of  a  city  milk  supply. 

Second  edition  to  be  published  February,  1900. 


WYMAN.    (*)"  Bovine  Obstetrics."     By  M.  G.  De  Bruin. 
Translated  by    W.  E.  A.  Wyman,  M.D.V..V.S. 

See  also  "De  Bruin." 


—  (•)"  Catechism  of  the  Principles  of  Veterinary  Surgery." 
By  W.  E.  A.  Wyman,  M.D.V..V.S.  Cloth,  size  6x9, 
321  pages 3  50 

Concerning  this  new  work  attention  is  called  to  the 
following  points: 

1.— It  discusses  the  subject  upon  the  basis  of  veterinary  investigations. 

2.— It  does  away  with  works  on  human  pathology,  histology,  etc. 

3.— It  explains  each  question  thoroughly  hoth  from  a  scientific  as  well 

as  a  practical  point  of  view. 
4.— It  is  writen  by  one  knowing  the  needs  of  the  student. 
5._It  deals  exhaustively  with  a  chapter  on  tumors,  heretofore  utterly 

neglected  in  veterinary  pathology. 
6.— The  only  work  in  English  specializing  the  subject. 
7.— The  only  work  thoroughly  taking  into  consideration  American  as 

well  as  European  investigations. 
8.— Offering  practical  hints  which  have  not  appeared  in  print,  the 

result  of  large  city  and  country  practice. 


—  (f/'The    Clinical  Diagnosis  of  Lameness  in  the  Horse." 

By  W.  E.  A.  Wyman,  D.V.S.,  formerly  Professor  of 
Veterinary  Science,  Clemson  A.  &  M.  College,  and 
Veterinarian  to  the  South  Carolina  Experiment 
Station.     Cloth,  size  6x9  1-2,  182  pp.,  32  illus. . .  .2  50 


(l)"Tibio-i)eroneal   Neurectomy  for  the  Relief  of  Spavin 
Lameness."    By  W.  E.  A.  Wyman,  M.D.V.,  V.S. 
Boards,  size  6  x  9,  30  pages,  illustrated 50 

Anyone  wanting  to  perform  this  operation  should  procure 
this  little  treatise ;  he  will  And  it  of  considerable  help.— The 
Veterinary  Journal. 


ZUILL,.        "Typhoid     Fever;     or     Contagious     Influenza 
in  the   Horse."     By   Prof .  W.  L.  Zulll,   M.D..D.V.S. 

Pamphlet,  size  6x9  1-4,  29  pages 25 


ZUNDEL.      "The    Horse's   Foot   and    Its   Diseases."    By 

A.  Znndel,  Principal  Veterinarian  of  Alsace  Lorraine. 
Translated  by  Dr.  A.  Liautard,  V.S.  Cloth,  size 
5x7  3-4,  248  pages,  illustrated 2  00 


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